Image information displaying system and hologram display apparatus

ABSTRACT

An image information displaying system comprises a transparent support, a hologram screen attached to the transparent support, a radiation unit for radiating image information on the hologram screen, a sensor for detecting the ambient condition within the viewing angle of the hologram screen, and a controller for controlling the radiation unit based on the signal from the sensor. The image information displaying system, which is inexpensive, long in service life, superior in eye-catching effect and low in running cost, consumes less energy and is controlled by a central control unit connected thereto through a communication line. The lower end of the hologram screen is 80 to 180 cm from the floor level.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an image information displayingsystem and hologram displaying apparatus, capable of being installed ina showroom and so forth, for presenting image information includingmoving and still images.

[0003] 2. Description of the Related Art

[0004] First View Point of Prior Art

[0005] Image information displaying systems are widely used to presentimage information including moving and still images to passersby andviewers in front of showrooms. These systems are composed of a screenand a unit for supplying image information to the screen.

[0006] A typical image information displaying system employs avideotape, an optical disk, or slides to store image information, avideo deck, an LD player, or a projector to reproduce the imageinformation, and a CRT or a liquid-crystal panel to display thereproduced image information.

[0007] Poorly presented image information hardly attracts the attentionof passersby, and therefore, hardly realizes advertising andeye-catching effects.

[0008] Image information to be displayed must be adjusted so that it canbe recognized easily by people. If image information is poorly adjustedand is hardly recognizable, it will not appeal to, or attract theattention of, people.

[0009] Image information must be adjusted according to ambientconditions around the location where the image information displayingsystem is installed. It is very difficult to adjust image informationbeforehand. In particular, when the system is installed outdoors orfacing the outdoors, the values of parameters used to adjust imageinformation vary from hour to hour and are dependent on weather andseasonal conditions.

[0010] Usually, the system is continuously operated to always displayimage information. The system, therefore, consumes a large amount ofpower and energy, has high running costs, and has a short service life.

[0011] Second Viewpoint of Prior Art

[0012] A conventional image information displaying system comprising ascreen and a means for supplying image information to the screen findsapplication as a means for presenting image information, as stillpictures or a moving picture, from a showroom or the like to passersbyand other viewers in general.

[0013] Specifically, the image information recorded in the videotape,the optical disk, slides or the like is reproduced and presented using adisplaying system such as a CRT or a liquid crystal panel connected tovarious reproduction or playback apparatuses including a video deck, anLD player and a projector.

[0014] Consider the case in which an image information displaying systemis used for presenting information to chain store outlets or branchoffices located over wide areas.

[0015] In such a case, for the image information displaying system ofeach outlet or branch office to be operated practically, it is necessaryto teach the operating know how to each outlet and branch office and totrain the staff therein. This poses no problem if the image informationdisplaying systems are installed within a small area or in a smallnumber or the workers are limited in number. In the case where the imageinformation systems are installed over a wide area, in many units ormust be operated by many workers, however, the presentation ofinformation requires the troublesome and expensive work of training theworkers, distributing operating manuals, etc.

[0016] No available image information displaying system placessufficient emphasis on reduced costs for management and practicaloperation (education and training as examples) of each of a multiplicityof systems installed over a wide area.

[0017] In the case where the image information displaying system is usedfor displaying a commercial for a commodity, for example, the merepresentation of image information on the image displaying system canhardly attract the attention or interest of passersby or viewers, makingeffective advertisement difficult. In other words, the eye-catchingeffect is small.

[0018] The operation of an image information displaying system,therefore, requires an appropriate adjustment of the image informationto make it easily visible to passersby and viewers and to attract theirattention even more. The adjustment for presenting more visible imageinformation may include brightness adjustment, color drift correction,determination of appropriate hue or adjustment of the position at whichthe image is displayed.

[0019] As long as the image information is difficult to recognize due toinsufficient adjustment, the image information is less appealing topassersby and viewers and a good eye-catching effect is often difficultto produce.

[0020] To cope with the above-mentioned problems and to improve theeye-catching effect, a method has been conceived to install a means foradjusting the image information with each image information displayingsystem. The adjusting means, however, makes the image informationdisplaying system more expensive. In addition, the maintenance andinspection as well as the operation of the adjusting means oftenincreases the system cost.

[0021] Also, since the image information displaying system is kept inoperation for presenting image information, the reproduction or playbackunit and the display unit thereof are also kept in operation. The powerconsumed by these units is so large as to pose problems from theviewpoints of energy saving and running cost. Further, the protractedoperation time of the reproduction unit and the display unit shortensthe service life thereof.

[0022] Third View Point of Prior Art

[0023] New display systems employing plasma display units, thinliquid-crystal display units, and projection television units are beingdeveloped to present still and moving images to passersby in front ofshowrooms.

[0024] To enhance an advertising effect, these systems must be madelarger. The larger systems, however, frequently provide an oppressivefeeling to viewers. This limits their possible locations, usability, anddesign flexibility.

[0025] To solve the problem and realize a high advertising effect, adisplay system employing a hologram screen has been proposed.

[0026] The hologram screen, as will be explained later in detail,consists of a transparent base and a thin-film hologram element attachedthereto. The hologram element has interference fringes. When lightcontaining image information is emitted onto the interference fringes,the light forms a real image, which is diffracted by the hologramelement. Viewers see the real image reproduced on the hologram element.

[0027] The hologram element is transparent, and the hologram screen doesnot require a power source or a driver. The hologram screen, therefore,needs only a small installation space and the designing freedom thereofis good.

[0028] One problem of the hologram screen is that it has a limitedviewing angle within which people can see images on the hologram screen.Accordingly, the hologram screen must be carefully installed so thatviewers can correctly see images thereon.

[0029] To achieve correct positioning of the hologram screen, manyexperiments have been made. For example, a mirror method surrounds alight diffuser with mirrors to produce object beams that irradiate aphotosensitive material from different directions. The object beams anda reference beam record intricate interference fringes on thephotosensitive material. The photosensitive material is used as ahologram element of a hologram screen.

[0030] Even the hologram screen made by the mirror method has a limitedviewing angle. Namely, the hologram element of the mirror methodinvolves parts where no light diffuser is recorded, and therefore,images on the hologram screen are partly invisible depending on viewer'spositions. At some position, images on the hologram screen provide lowbrightness, different colors, or poor quality for viewers.

[0031] In this way, it is very difficult to sufficiently expand theviewing angle of a hologram screen.

SUMMARY OF THE INVENTION

[0032] In view of the first viewpoint of the prior art, a first objectof the present invention is to provide an image information displayingsystem capable of providing excellent eye-catching effects, reducedenergy consumption and running costs, and an extended service life.

[0033] In order to accomplish the object, a first aspect of the presentinvention provides an image information displaying system having atransparent support, a hologram screen attached to the support, aprojector for projecting image information onto the screen, a sensor forsensing ambient conditions within a viewing angle of the hologramscreen, and a controller for controlling the projector according tosignals from the sensor.

[0034] The hologram screen may be of a transmission type or of areflection type.

[0035] To improve an eye-catching effect, preferably, the hologramscreen may be transparent so that viewers may see a background andexhibits behind the screen.

[0036] The transparent hologram screen and support may achieve an effectof suddenly displaying image information in a vacant space to greatlyattract the attention of people.

[0037] The transparent hologram screen does not disturb the view ofother people, thereby improving the degree of freedom in designing andinstalling the system.

[0038] The transparent support may be a show window made of glass orresin, a front or rear window of a mobile body such as a car, a vessel,an airplane, or a train, a window panel of an office or a shop, or awall made of glass or plastics of a guest room, or any other space.

[0039] The projector may be a slide projector, an overhead projector(OHP), or any device for projecting moving and still images.

[0040] The projector may receive image information from an externalsupply unit, which may be a player of videotapes and optical disks, orinformation processing equipment such as a personal computer connectedto the Internet.

[0041] The projector emits a beam of image information onto the hologramscreen, which diffracts and diffuses the beam into a conical area. Onlywithin the conical area is the image information visible.

[0042] More precisely, each beam of image information from the projectorforms a conical area on the hologram screen, and a viewer can see animage only in an overlap of such conical areas. These conical areasdefine a viewing angle of the hologram screen. The viewing angle will beexplained later in detail.

[0043] A plurality of image information displaying systems may beinstalled and linked to one another. In this case, each system may havea sensor (embodiment A2), or the systems may share a single sensor.

[0044] The operation of the first aspect of the present invention willbe described in the following.

[0045] The sensor senses ambient conditions in the viewing angle of thehologram screen, and the controller controls the projector according tosignals from the sensor.

[0046] This system is capable of automatically starting, optimizing, andstopping image information provided by the projector according toambient conditions detected in the viewing angle of the hologram screen.

[0047] For example, if the illuminance in the viewing angle is high, thesystem increases the brightness of image information, or changes theimage information itself to another having a higher brightness, so thatviewers may easily recognize the images.

[0048] If voices are sensed in the viewing angle, the system determinesthat there are people in the viewing angle and activates the projectorto present image information to the people.

[0049] In this way, the present invention automatically changes theconditions and kinds of image information and starts and stops imageinformation according to ambient conditions that vary from hour to hour.

[0050] The system provides eye-catching image information to stronglyattract people's attention.

[0051] The projector may be automatically started and stopped accordingto situations, to shorten an actual operation time of the projector,thereby reducing power consumption and running costs.

[0052] Shortening the operation time of the projector may extend theservice life thereof.

[0053] In this way, the system of the present invention reduces energyconsumption and running costs and extends the service life.

[0054] A second aspect of the present invention defines the viewingangle of the hologram screen in an area where brightness is K0/2 or over(K0 being a brightness value at a front center point of the hologramscreen).

[0055] Brightness within the viewing angle of the hologram screen ishigh and, therefore, viewers in the viewing angle may clearly recognizeimages on the hologram screen. Accordingly, images within the viewingangle achieve a high eye-catching effect.

[0056] In an area where brightness is below K0/2, viewers may recognizeimage information but may hardly grasp the contents thereof. In thiscase, the eye-catching effect of the image information is low. Thebrightness of the hologram screen is highest at the center thereof.

[0057] The details of K0 and the viewing angle of a hologram screen willbe explained later.

[0058] A third aspect of the present invention employs, as the sensor,an illuminance sensor so that the image information displaying systemmay present optimum image information in the viewing angle of thehologram screen.

[0059] A fourth aspect of the present invention provides the imageinformation displaying system with a speaker for providing audioinformation. In this case, the sensor is a volume sensor.

[0060] This arrangement provides audio information as well as imageinformation, thereby providing an improved eye-catching effect.

[0061] The volume sensor senses a sound volume in the viewing angle ofthe hologram screen and feedback-controls the speaker, to optimize audioinformation as well as image information according to ambientconditions. If not needed, the speaker may be stopped to reduce runningcosts and prolong the service life.

[0062] A fifth aspect of the present invention uses the sensor to detectthe presence of people in the viewing angle of the hologram screen.

[0063] If people enter the viewing angle of the hologram screen, thefifth aspect activates the projector to project image information, orswitches displayed image information to another.

[0064] If no image information is displayed, the hologram screen isinconspicuous to passersby. Accordingly, the fifth aspect may provide ahigh eye-catching effect by suddenly displaying image information in avacant space where the hologram screen is installed.

[0065] The fifth aspect is capable of activating the projector only whenpeople are present in the viewing angle of the hologram screen. Thisshortens an operation time of the projector, reduces power consumptionand running costs, and prolongs the service life of the system.

[0066] The sensor may be an infrared sensor, a voice sensor, a vibrationsensor, a weight sensor arranged on the floor, etc. A single sensor, aplurality of sensors, or a various types of sensors may be used incombination.

[0067] The sensor may sense not only people entering the viewing angleof the hologram screen but also people going out of the viewing angle.If the sensor senses that people enter the viewing angle, the controllerstarts the projector to project image information, and if the sensorsenses that people exit the viewing angle, the controller stops theprojector.

[0068] The arrangement of the fifth aspect secures the effect of thepresent invention.

[0069] A sixth aspect of the present invention installs the imageinformation displaying system in a mobile body.

[0070] If the hologram screen is transparent, it does not bother thesight of people. In this case, the system does not block a driver of themobile body from seeing the outside through the hologram screen.Accordingly, the system can be installed in a mobile body.

[0071] The system installed in a mobile body is used to display driverassisting information such as navigation information, or alarminformation to the outside of the mobile body.

[0072] If the mobile body is a car, the system may display imageinformation for passengers in the rear seat of the car.

[0073] A seventh aspect of the present invention arranges the imageinformation displaying system between two seats of a mobile body.

[0074] This arrangement prevents the hologram screen from being exposedto the sun, thereby extending the service life thereof.

[0075] More precisely, this arrangement prevents discoloration andperformance deterioration due to ultraviolet rays and heat from the sun.

[0076] An eighth aspect of the present invention makes the hologramscreen of the image information displaying system retractable when it isnot used.

[0077] This arrangement effectively uses a limited space in a mobilebody. When the hologram screen is retracted, it is protected from beingdiscolored or deteriorated due to ultraviolet rays and heat from thesun. This arrangement also makes the installation of the system into amobile body easier.

[0078] The retractable hologram screen may be realized by winding,folding, or detaching of the screen.

[0079] The hologram screen may be arranged on a sunroof. In this case, aviewer sets himself or herself on a fully reclined seat to see imageinformation.

[0080] The hologram screen may be integrated with or embedded in a seatof a mobile body (FIG. 14).

[0081] A ninth aspect of the present invention employs, as the sensor ofthe image information displaying system, a vibration sensor. Thevibration sensor senses the vibration of a mobile body in which thesystem is installed. In response to signals from the vibration sensor,the controller of the system corrects a blur of image information on thehologram screen due to the vibration of the mobile body (FIG. 15).

[0082] A tenth aspect of the present invention employs the vibrationsensor to suppress the vibration of the projector of the system againstthe vibration of the mobile body in which the system is installed (FIG.16).

[0083] When the mobile body vibrates, the projector may provide blurredimages. This problem is serious when the mobile body is large such as abus or a truck because the vibration thereof is also large.

[0084] The tenth aspect uses the vibration sensor to detect vibration,electrically corrects image information according to signals from thevibration sensor, and projects the corrected image information from theprojector onto the hologram screen, thereby correcting a blur of imageson the screen.

[0085] The tenth aspect may have a mechanism for suppressing thevibration of the projector. The mechanism is driven in response tosignals from the vibration sensor, to correct a blur of images on thehologram screen.

[0086] The system of the tenth aspect is capable of displaying blur-freeimages in the mobile body.

[0087] The mechanism for suppressing the vibration of the projector maybe a damper or a piezoelectric actuator.

[0088] An eleventh aspect of the present invention connects imageinformation displaying systems to a central control unit through acommunication circuit and controls the systems by the central controlunit.

[0089] The central control unit centrally controls and manages thesystems, to save manpower.

[0090] The communication circuit may be a public or private voicecircuit (telephone circuit), a moving image circuit of, for example, acable television service using optical cables, or a radio circuit suchas a communication satellite digital circuit. Any wire or wirelesscommunication circuit can be used for the eleventh aspect. The Internetcan also be used.

[0091] Image information to be displayed may be held at the imageinformation displaying systems or at the central control unit. In thelatter case, the central control unit can centrally manage imageinformation, to reduce management costs.

[0092] For example, each image information displaying system isinstalled in each branch office, and the central control unit in thehead office, which distributes new product information simultaneously tothe branch offices so that the branch offices may release anannouncement of the new product at the same time. This saves the laborof sending materials related to the new product to the branch officesbeforehand.

[0093] In another example, each image information displaying system isinstalled in each chain store, and the central control unit in the headoffice. This provides the same effect as the above example. In addition,updating commodity information is made only in the central control unit.This eliminates each chain store's labor of updating the commodityinformation.

[0094] If the central control unit must hold image information, it ispreferable to employ a high-speed communication circuit such as awide-band private circuit to distribute the image information to thebranch offices or chain stores.

[0095] A twelfth aspect of the present invention makes the centralcontrol unit receive signals from the sensor of each system through acommunication circuit and controls the projector of the system inquestion according to the signals to project image information onto thehologram screen of the system.

[0096] This arrangement secures the effect of the present invention.

[0097] A thirteenth aspect of the present invention records a diffuseron the hologram screen of the image information displaying system.

[0098] This aspect provides an effect of displaying full-color images onthe hologram screen.

[0099] In view of the above-mentioned problems in the second viewpointof the prior art, a second object of the invention is to provide aninexpensive image information displaying system which has a lowmaintenance/inspection cost, a low running cost and a long service life.

[0100] In order to achieve the second object described above, accordingto a 14th aspect of the invention, there is provided an imageinformation displaying system comprising a transparent support, ahologram screen attached to the transparent support, and a radiationunit for irradiating the hologram screen with image information, theimage information displaying system being controlled by a centralcontrol unit connected thereto through a communication line.

[0101] The central control unit can be configured as a mainframecomputer or various work stations or the like, for example. Forimproving the effect of the invention further, each central control unitis desirably connected with a great number of image informationdisplaying systems.

[0102] Various communication lines are available for use including theaudio communication lines such as the telephone network and leasedlines, optical fiber cables for distribution of image sequences used onthe cable TV or the like, radio channels such as the CS digital lineusing an earth satellite, or various other wire and wireless channels. Acomputer network such as the Internet can also be used.

[0103] A transmission-type hologram screen can be used as theabove-mentioned hologram screen. A hologram screen of a reflection typeis another candidate.

[0104] A transparent hologram screen is desirable for assuring animproved eye-catching effect. This makes possible a configuration inwhich viewers can see commodities exhibited and the background behindthe hologram screen through the hologram screen.

[0105] Also, for its ability to present image information suddenly in anapparently vacant space (although a transparent support and a hologramare actually installed), the hologram can attract the attention andinterest of viewers considerably.

[0106] Further, the image information displaying system, which can beconfigured to not interfere the viewing field of viewers, can beinstalled with a higher freedom.

[0107] The transparent support includes window glass made of varioustypes of glass or plastics, the rear and front glass of various mobilebodies (such as automobiles, seagoing vessels, airplanes and electrictrams), the window glass used in branch offices and retail outlets, andthe glass window panes and transparent walls arranged around a guestroom or the like.

[0108] The radiation unit, on the other hand, includes a slideprojector, an OHP (overhead projector), a liquid crystal projector, amotion picture projector and various other devices capable of radiatingstill images and image sequences.

[0109] The image information can be supplied to the radiation unit alsofrom an external source. External information sources includereproduction or playback units such as videotape and optical diskplayers and information processing systems such as personal computersconnected to the internet. Also, image information can be distributedfrom a central control unit.

[0110] The operation and effects of the 14th aspect of the inventionwill be explained.

[0111] The image information displaying system according to this aspectof the invention is so configured as to be controlled by a centralcontrol unit connected thereto through a communication line.

[0112] The central control unit makes possible the collective managementand practical operation of the image information displaying systems,thereby reducing the cost for management and practical operation whichotherwise would be required on the part of the image informationdisplaying system. The staff and labor cost can thus be reduced.

[0113] Since the job of management and practical operation of the imageinformation displaying system can be left to the central control unit,the construction of each image information displaying system issimplified for a correspondingly reduced cost thereof. In other words,the image information displaying system can be constructed in sosimplified a fashion as to have only the functions of displaying imagesand accepting the control from the central control unit.

[0114] The simplicity of the image information displaying system reducesthe system cost on the one hand and the maintenance cost for repair andinspection as well as the running cost at the same time. The simpleconstruction is also a factor in reducing the number of system faults.

[0115] Further, the various adjustments of the parts of the imageinformation displaying system which can be accomplished from the centralcontrol unit facilitates the system operation. The labor of educatingand training the workers can thus be saved. Also, the simplicity of thesystem configuration can produce an image information displaying systemeasy to handle even by unskilled workers.

[0116] An example of the mechanism for management and operation is adiagnosis mechanism for discovering a fault and deterioration at anearly time. Provision of the diagnosis mechanism in the central controlunit lengthens the service life of the system while at the same timepreventing the image information displaying system from beingcomplicated in structure and increased in cost.

[0117] It is also possible to start and stop the operation of the imageinformation displaying system at a preset time. The system can besuspended from operation or put into continuous operation or otherwisecontrolled by the central control unit. Since the image informationdisplaying system can thus be operated only when required and can becontrolled in fine detail, the system life is lengthened and the runningcost thereof is reduced.

[0118] In addition, emergency and newspaper information, as well as theoriginal image information to be displayed, can be selected as desiredby the management thereof.

[0119] The hologram screen irradiated with the image informationdisplays the image by diffraction and scattering the radiated beamcontaining the image information. The hologram which has no power supplyand no driving unit contributes to reduction in running cost and savesenergy for the image information displaying system according to theinvention.

[0120] As described later, the hologram screen requires some correctionand adjustment for displaying a clear-cut, normal image having a strongimpact on, and giving a vivid impression to, viewers.

[0121] The image information displaying system according to thisinvention, which can be adjusted and corrected by the central controlunit, eliminates the need of the various troublesome jobs of adjustmentand correction on the part of the image information displaying system,thus reducing the management cost and labor in general.

[0122] The data for image information radiated can be incorporated ineither the image information displaying system or the central controlunit. In the latter case, the image information can be centrallycontrolled by the central control unit for a reduced management cost.

[0123] Assume, for example, that a party for unveiling a new product isheld in all branch offices at the same time. The image informationdisplaying system according to the invention is installed in each branchoffice and the central control unit in the head office from which theinformation on the new product can be distributed to the branch officesin various areas. This saves the trouble of distributing the informationon the new product to various areas in advance.

[0124] Another example application is to install the image informationdisplaying system at each outlet of a chain store or the like and thecentral control unit at the headquarters. This has the same effect asthe preceding case. Further, the information on commodities can beupdated simply by updating the image information incorporated in thecentral control unit.

[0125] For locating the image information in the central control unit, ahigh-speed communication line (wide-area leased line, for example) isdesirably used.

[0126] The 14th aspect of the invention described above can thus providean inexpensive image information displaying system with low running,maintenance and inspection costs and a long service life.

[0127] A 15th aspect of the invention is desirably configured in such away that the central control unit alone corrects the image information,or in such a way that the central control unit or a relay interposedbetween the central control unit and the image information displayingsystem corrects the image information.

[0128] The provision of the relay permits part of the processing in thecentral control unit to be transferred to the relay. The processing canthus be distributed between the central control unit and the relay,thereby making it possible to improve the stability and speed of theprocessing of the whole network including the central control unit andthe image information displaying system.

[0129] In addition, a local area network can be formed with the relay asa base. Thus finely detailed control meeting local requirements is madepossible.

[0130] Also, the following general properties of the hologram screen areknown. Specifically, the scattered beam emitted from the hologram screenoften has a peak in a specified wavelength range, even when the incidentbeam is white, often with the result that the tone of the imagereproduced on the hologram screen is different from that of the radiatedbeam.

[0131] For this reason, image color adjustment and color correction arecrucial in using the hologram screen.

[0132] The image information displaying systems distributed to variouspoints are adjusted by individual workers. Due to the difference incolor sense from one person to another, however, it is very difficult toadjust and correct the color of the images displayed on all the imageinformation displaying systems to the same state.

[0133] The collective control using the central control unit as in the15th aspect of the invention, however, can maintain the same state ofthe image information displayed on a multiplicity of systems distributedover a wide area. At the same time, the labor of the workers is reduced.This labor saving effect can reduce the cost and trouble of the wholemanagement.

[0134] The fact that the image information can be corrected by thecentral control unit or the relay makes it possible to display a correctimage normally free of a color drift between the radiated beam and thedisplayed image.

[0135] Also, the elimination of the need of correction and adjustment onthe part of the image information displaying system can save theequipment for image information correction which otherwise would berequired in each image information displaying system. The cost of theimage information displaying system can thus be reduced. Further, sincethe cost for repair and inspection and the running cost of thecorrection unit is not required, the system cost can accordingly bereduced.

[0136] Furthermore, in displaying a commercial of a commodity as imageinformation, for example, the sponsor of the commercial who emphasizesthe image of the commodity may request the faithful reproduction of finecolor texture of the image information.

[0137] With the image information displaying system according to the15th aspect, the image information can be collectively corrected at thecentral control unit and therefore such a request can be readily met.

[0138] It is also possible to incorporate the image information in thecentral control unit, and after correction, distribute it among theimage information displaying systems for display. The image informationstored in each image information displaying system can also be correctedindividually.

[0139] According to a 16th aspect of the invention, the above-mentionedcorrection is preferably that of a trapezoidal distortion.

[0140] In order to prevent the radiated beam from directly entering theeyes of the viewer, the radiation unit is generally installed at anangle to the hologram screen. The radiation unit, therefore, is oftenlocated at a position diagonally above or below the hologram screen.

[0141] Locating the radiation unit at such a position may cause atrapezoidal distortion of the image on display as shown in FIG. 33a.

[0142] According to this aspect of the invention, as shown in FIG. 33b,the trapezoidal distortion of the image information is reverselycorrected by the central control unit in advance. Therefore, as shown inFIG. 33c, the image information displaying system can display a normalimage.

[0143] As in the 15th aspect, the image information displaying system isnot required to correct the trapezoidal distortion. Therefore, thetrapezoidal distortion correction unit can be eliminated from the imageinformation displaying system, and the cost of the image informationdisplaying system can be reduced.

[0144] Other details are similar to those of the 15th aspect.

[0145] Also, as the 16th aspect of the invention, the correctiondescribed above is desirably at least one of the processes including thecolor adjustment, color correction, image position adjustment, imagebrightness adjustment and the image contrast adjustment.

[0146] As a result, a clear-cut image having a strong impact on viewerscan be displayed.

[0147] According to a 17th aspect of the invention, the imageinformation displaying system includes means for supplying audioinformation, and the central control unit or the relay is preferablyconfigured to correct the audio information.

[0148] The provision of the means for supplying audio information leadsto an image information displaying system having a superior eye-catchingeffect which can present both image information and audio information.

[0149] As in the 15th aspect, the correction of audio information is notrequired on the part of the image information displaying system, andtherefore the audio information correction unit can be eliminated fromthe image information displaying system. The cost of the imageinformation displaying system can thus be reduced.

[0150] Other details are similar to those of the 15th aspect.

[0151] The processing for correcting the audio information includes theautomatic starting and automatic stopping of the system, adjustment ofsound volume or sound quality, selection and switching of audioinformation, etc.

[0152] The means for supplying audio information is a speaker, forexample.

[0153] According to an 18th aspect of the invention, the imageinformation displaying system preferably comprises a sensor fordetecting the ambient conditions within the viewing angle of thehologram screen and a radiation control unit configured to control theradiation unit based on the signal from the sensor.

[0154] As described above, in the case where the image informationdisplaying system is used for presenting a commercial of a commodity,the mere image information appearing on the image information displayingsystem fails to attract the attention and interest of passersby orviewers, thereby making effective advertisement and publicity difficult.In other words, the eye-catching effect is low.

[0155] When using an image information displaying system, therefore, itis necessary to adjust the image information to a most visible form forpassersby and viewers in such a manner as to attract their maximumattention. As long as the system is not sufficiently adjusted and theimage information remains difficult to recognize, the image informationis less appealing to passersby and viewers and can rarely produce a goodeye-catching effect. The adjustment for this purpose may includeadjusting the brightness for making the image easy to see, correctingthe color drift, selecting an appropriate hue and adjusting the positionat which the image is displayed.

[0156] The effective adjustment of the image information depends on theenvironment in which the image information displaying system isinstalled. Therefore, it has thus far been difficult to presetadjustment values for the image information displaying system.Especially in outdoor applications or applications at a location facingthe outdoor environment, the optimum adjustment values for the imageinformation system undergo a constant change with time, weatherconditions and the season of the year.

[0157] With the image information displaying system according to the18th aspect of the invention, the condition and type of imageinformation can be changed or the presentation of the image informationcan be started or stopped automatically in accordance with the variousambient conditions undergoing a constant change within the viewingangle.

[0158] In the case where the ambient illuminance within the viewingangle is high, for example, the brightness of the image information isincreased or the image information is changed to the one of higherbrightness or otherwise image information easily visible to viewers canbe supplied.

[0159] When the voice of a person is sensed within the viewing angle,for example, the presence of a viewer within the viewing angle isassumed and the radiation unit is activated to supply the imageinformation to the particular viewer.

[0160] As a result, the image information can be supplied with such ahigh eye-catching effect as to attract the attention of the viewersufficiently.

[0161] In the image information displaying system according to the 18thaspect, the radiation unit can be configured to operate automatically asrequired and therefore the substantial operation time of the radiationunit can be shortened. The power consumption of the radiation unit canthus be saved for a lower running cost.

[0162] Also, the shorter operating time of the radiation unit canlengthen the service life thereof.

[0163] As described above, according to the 18th aspect of theinvention, an image information displaying system is provided which hasa high eye-catching effect, is low in running cost and has a longservice life.

[0164] Further, a plurality of image information displaying systemsaccording to the invention can be used in coordination with each otherthrough a central control unit. In such a case, the image informationdisplaying systems each can be provided with a sensor (embodiment B2) orcan share a sensor.

[0165] According to a 19th aspect of the invention, the viewing angle isdesirably located in an area having a brightness of at least K0/4 (K0represents the brightness value at the front center of the hologramscreen).

[0166] The brightness of the hologram screen as viewed from within theabove-mentioned viewing angle is so high that the viewer standing withinthe viewing angle can recognize the image information on the hologramscreen as a bright and clear-cut image. The image information displayingsystem according to this aspect, therefore, can present imageinformation having a good eye-catching effect.

[0167] In the brightness range of less than K0/4, the viewer canrecognize the image information but may find it difficult to comprehendthe contents of the image information. A reduced eye-catching effect isthe probable result.

[0168] The hologram screen has such a feature that the image informationissued from the radiation unit and impinged on the hologram screen canbe observed on the hologram screen only from within a conical spaceformed by diffraction and diffusion of the image information (radiatedbeam).

[0169] The image information on the hologram screen, therefore, isvisible only in an area where conical spaces formed by the imageinformation (radiated beam) impinged on various parts of the hologramscreen are overlapped. This area constitutes a viewing angle, which willbe described later in detail.

[0170] The brightness of the hologram screen, on the other hand, assumesthe highest value at the center thereof.

[0171] According to a 19th aspect of the invention, the sensor describedabove is preferably an illuminance sensor. This makes it possible torealize an image information displaying system capable of presentingoptimum image information corresponding to the brightness within theviewing angle.

[0172] According to a 20th aspect of the invention, the sensor isdesirably a volume sensor.

[0173] The sound volume within the viewing angle can be sensed by thevolume sensor. Thus, the sound volume information with the sound volumemost suitable for the prevailing ambient conditions can be supplied inaddition to the image information. If the sound volume information isnot required, a device such as the speaker for supplying audioinformation can be deactivated for reducing the running cost andlengthening the service life of the system.

[0174] According to a 21st aspect of the invention, the sensor isdesirably configured to sense the entry of the viewer into the viewingangle.

[0175] Thus, an image information displaying system is realized inwhich, when a viewer enters the viewing angle of the hologram screen,the radiation unit is activated to radiate the image information or theimage information is switched.

[0176] The hologram screen is so inconspicuous that it is not easilyrecognized by the viewer until image information is displayed thereon.For this reason, the invention makes it possible to present a situationin which image information suddenly presents itself in a thus far emptyspace and thus a good eye-catching effect can be produced.

[0177] Also, as described above, according to this invention, theradiation unit can be activated as soon as the viewer enters the viewingangle. The operation time of the radiation unit can thus be shortenedfor a reduced power consumption and running cost. The service life ofthe system can also be lengthened.

[0178] The above-mentioned sensor can include an infrared sensor, anaudio sensor, a vibration sensor or a weight sensor installed on thefloor. These sensors can be used individually or a plurality of sensorsor sensor types can be used in combination.

[0179] The above-mentioned sensor desirably detects both the entry intoand exit from the viewing angle of the viewer. In response to the signalfrom this sensor, the radiation control unit desirably causes the imageinformation to be radiated from the radiation unit when the viewerenters the viewing angle and deactivates the radiation unit when theviewer leaves the viewing angle.

[0180] As a result, the effect of the invention can be secured morepositively.

[0181] According to a 22nd aspect of the invention, the imageinformation displaying system is desirably mounted on a mobile body.

[0182] The use of a transparent hologram can produce a transparent imageinformation displaying system which does not interfere with the field ofview. Such an image information displaying system has the effect ofproviding a lesser chance of preventing both the driving, and theobservation of the outside, of the mobile body. The image informationdisplaying system according to the invention thus is suitably installedon a mobile body.

[0183] The image information displaying system installed on a mobilebody can be used for displaying driving-support information like the carnavigation system or a warning to other mobile bodies.

[0184] In the case where the mobile body is an automotive vehicle, theimage information displaying system is usable as a display unit forrear-seat passengers, for example.

[0185] According to a 23rd aspect of the invention, the imageinformation displaying system is desirably installed between at leasttwo seats in a mobile body (FIG. 29).

[0186] As a result, the hologram screen is prevented from being directlyexposed to sunlight and thus early degeneration of the hologram screenis prevented.

[0187] Specifically, it is possible to prevent discoloring orperformance deterioration due to the ultraviolet light and the heat ofdirect sunlight.

[0188] According to a 24th aspect of the invention, the hologram screenis desirably retractable into an appropriate means when not in use.

[0189] This makes possible the effective utilization of the limitedinternal space of the mobile body. Also, the retraction of the hologramscreen when not in use can further prevent the discoloring, theperformance reduction and deterioration thereof which otherwise might becaused by the ultraviolet light and the solar heat. Further, other workin the mobile body may be facilitated.

[0190] Specifically, the hologram screen is desirably provided as aroll-up, folding or detachable type.

[0191] The hologram screen can also be arranged on the sunroof. In thiscase, the hologram screen can be configured in the form of full flatsheet on which the image information can be observed.

[0192] Another possible configuration is integrating the hologram screenwith or embedding it in the front passenger seat or the head rest (FIG.30).

[0193] According to a 25th aspect of the invention, the sensor is avibration sensor, and the radiation control unit is desirably configuredto correct the blur of the radiated image information caused by thevibration of the mobile body based on the signal from the vibrationsensor.

[0194] According to a 26th aspect of the invention, the sensor is avibration sensor and the radiation control unit is desirably soconfigured as to suppress the vibrations of the radiation unit due tothe vibrations of the mobile body based on the signal from the vibrationsensor.

[0195] In the case of installing various display units on a mobile body,the problem of image blurring due to vibrations of the mobile body isencountered especially by a display unit which projects the imageinformation by a radiation unit. This problem is especially serious forlarge-sized vehicles such as buses and trucks.

[0196] According to this invention, a blurred image is corrected in sucha manner that vibrations are detected by a vibration sensor, and thedata making up the image information is electrically corrected based onthe detected signal and radiated from the radiation unit.

[0197] Alternatively, a mechanism for suppressing the vibrations of theradiation unit can be provided and driven based on the signal from thevibration sensor to correct the image blurs.

[0198] These means can produce an image information displaying system bywhich image information can be viewed with little blurring on a mobilebody.

[0199] Means for absorbing the vibrations of the radiation unit includea damper and a piezo-actuator.

[0200] According to a 27th aspect of the invention, preferably, thecentral control unit or the relay receives the signal from the sensorthrough the communication line, and based on the same signal, controlsthe radiation control unit.

[0201] In the image information displaying system according to the 27thaspect, as in the embodiment B1 described later, the ambient conditionwithin the viewing angle of the hologram screen is detected by a sensor,and the resulting signal representing the ambient condition is appliedfrom the sensor to the central control unit or the relay. The centralcontrol unit or the relay, upon receipt of this signal from the sensor,can control the radiation control unit in keeping with the ambientcondition within the viewing angle.

[0202] As a consequence, the central control unit or the relay canperform various control operations such as activating and deactivatingthe radiation unit, switching the image information radiated from theradiation unit or correcting or adjusting the image information inaccordance with the ambient condition within the viewing angle.

[0203] In other words, according to this embodiment, the imageinformation displaying system can perform the control operation takingthe ambient condition of the image information displaying system intoconsideration, substantially free of manual operation. Also, an imageinformation displaying system high in energy-saving ability is provided.

[0204] According to a 28th aspect of the invention, a diffuser ispreferably recorded in the hologram screen.

[0205] This makes it possible to produce an image information displayingsystem capable of projecting a full-color image and to further improvethe eye-catching effect.

[0206] The diffuser described above can be a light diffuser such asground glass.

[0207] In view of the above-mentioned problems described in the thirdviewpoint of the prior art, a third object of the present invention isto provide a hologram displaying system capable of displaying a superiorimage and having a high eye-catching effect.

[0208] In order to achieve the third object described above, accordingto a 29th aspect of the invention, there is provided a hologramdisplaying system comprising a hologram screen, and a projector forprojecting an image beam on the hologram screen, wherein the lower endof the hologram screen is located at the distance of 80 to 180 cm fromthe floor level.

[0209] The hologram screen will be explained.

[0210] The hologram screen can be classified into a hologram oftransmission type for transmitting an image beam therethrough and ahologram screen of reflection type for reflecting an image beam. Thepresent invention can use either type of the screen.

[0211] As shown in FIGS. 51(a) to 51(f), 52(a) to 52(f), 53(a) to 53(f)described later, various shapes of screen can be used. Further, althoughthe hologram screen can be used with the image beam projected over theentire surface thereof to display an image as described with referenceto FIG. 54 later, the image beam can be projected on part of thehologram screen using the zoom function of the image projector todisplay the image.

[0212] The hologram screen of a transmission type is the one with theimage projector arranged at the back of the screen. The image beamprojected from the image projector is focused and forms a real image onthe hologram screen. A person can recognize the image by the diffractedlight scattered and transmitted from the real image.

[0213] The hologram screen of reflection type, on the other hand, is theone using the image projector arranged on the front side of the screen.The image beam projected from the image projector is focused and forms areal image on the hologram screen. A person can recognize the image bythe diffracted beam scattered and reflected from the real image.

[0214] In a method of fabricating the hologram screen, a beamconstituting an object beam diffused through a light diffuser such asground glass and a non-diffused beam constituting a reference beam areprojected on a photosensitive material to form interference fringes. Anexample of the fabrication method will be explained below.

[0215] In fabricating a hologram screen of a transmission type, as shownin FIG. 48, a coherent beam 34 radiated from a laser beam source 51 ischanged in light path by a mirror 511, and then split into two beams341, 342 by a half mirror 512.

[0216] After the beam 341 is scattered by a lens 516, transmittedthrough a light diffuser 52, and the resulting diffused beam isprojected as an object beam 36 on a photosensitive material 50.

[0217] The other beam 342 split by the half mirror 512 is changed inlight path by mirrors 513, 514, scattered by a lens 515, and projectedon the photosensitive material 50 as a reference beam 35. The referencebeam 35 and the object beam 36 form interference fringes on thephotosensitive material 50. In FIG. 48, the corrugation shows a model ofthe diffused beam.

[0218] In fabricating a hologram screen of a reflection type, on theother hand, as shown in FIG. 49, the reference beam 35 and the objectbeam 36 are projected from opposite sides of the photosensitive material50 to form interference fringes.

[0219] A PET film is attached to the surfaces of the photosensitivematerial 50 obtained by the process mentioned above to form protectivefilms, thus making up a hologram screen.

[0220] Various devices are usable as an image projector. They include aslide projector, an OHP (overhead projector), a projector, a movieprojector or other devices that can project an image beam of stillpictures and image sequences.

[0221] It is also possible to supply an image to the image projectorfrom external devices such as a videotape, an optical disk, a personalcomputer or other reproduction units. The reproduction unit can, ofcourse, be built into the projector. Further, the image can be suppliedfrom an external source using the telephone line, an earth satellite orthe like channel.

[0222] In the case where the height of the hologram screen is less than80 cm, the line of eyesight of the viewer is liable to departconsiderably from the viewing angle specific to the hologram element,often making it difficult for the viewer to observe the image of asuperior quality. This also applies in the case where the height of thehologram screen is more than 180 cm, in which case the image issometimes difficult to see for the same reason.

[0223] The “superior image” is defined as an image having a small colordifference with and having substantially the same brightness, contrastand luminance as the image beam projected from the projector.

[0224] Also, the hologram displaying system according to this inventioncan be installed either indoor or outdoor. For the hologram displayingsystem installed outdoor, the “floor level” indicates the ground level.

[0225] As shown in FIG. 55 described later, the floor level is definedas the floor level 311 on which a viewer 8 of the hologram displayingsystem stands.

[0226] Also, as shown in FIGS. 51(a) to 51(f), 52(a) to 52(f) and 53(a)to 53(f) described later, the hologram screen can assume various shapes.The lower end of the hologram screen is also shown in the drawings.

[0227] The hologram screen can be configured either in flat form or in acurved form having a radius of curvature.

[0228] The hologram screen can have a very thin portion. Any portionwhere a image visible to the viewer cannot be displayed, however, failsto play the role of the hologram screen of the image displaying systemaccording to the invention. Therefore, such a very thin portion cannotbe considered as a lower end. The lower end of the hologram screen canbe determined taking the above fact into consideration.

[0229] A hologram screen according to a 29th aspect of the inventionuses interference fringes. The hue and brightness of the image ondisplay, therefore, are varied depending on the angle at which the imageis viewed. In other words, the hologram screen has some portions easy toview and other portions difficult to view. The portion where a superiorimage is clearly visible is called the viewing angle.

[0230] The viewing angle will be specifically described with referenceto FIGS. 34 and 35.

[0231] The hologram screen has the feature that the image is invisiblefrom other than a conical space formed by diffraction and diffusion ofthe image beam impingeing on the hologram screen from the projector.

[0232] Therefore, the image is visible only in an area where individualconical spaces formed as the image beam impingeing on various portionsof the hologram screen are overlapped one over the other. This areaconstitutes a viewing angle.

[0233] In FIG. 34, the image beam 125 projected from an image projector12 fans out and reaches a hologram screen 11. The image beam 125 thathas impinged on the upper end 112 of the hologram screen 11 is scatteredand transmitted while fanning out. Also, the image beam 125 that has hitthe lower end 111 of the hologram screen 11 also fans out.

[0234] Similarly in FIG. 35, the image beam 125 that has impinged on theleft end 113 and the image beam 125 that has impinged on the right end114 of the hologram screen 11 also fan out.

[0235] The foregoing description refers to the plan views of FIGS. 34and 35, and therefore the diffusion of the image beam 125 is expressedas “fan out”. Actually, however, the image beam assumes a conical shapeas it diffuses into the space.

[0236] The image displayed on the hologram is known to become difficultto view when the brightness of the image decreases to less than one halfof the central brightness. The central brightness is defined as thebrightness of the image at the center of the hologram screen.

[0237] Consequently, the viewing angle 89 on the hologram screen 11represents the sectorial area in the diagrams of FIGS. 34 and 35.

[0238] Now, the operation and effects of the 29th aspect of theinvention will be explained.

[0239] In the hologram displaying system according to this invention,the hologram screen is installed under the above-mentioned conditions.The viewing angle of the hologram screen, therefore, is included in theline of sight of the viewer.

[0240] As described above, the interior of the viewing angle is an areawhere a superior image is visible. Therefore, the hologram displayingsystem according to this invention can display a superior image.

[0241] In this respect, the hologram displaying system according to the29th aspect of the invention can display an image highly appealing tothe viewer. In addition, the hologram screen is easily configured to betransparent, and therefore, the viewer feels that an image is projectedin an otherwise empty space.

[0242] Consequently, the hologram displaying system according to the29th aspect of the invention has the effect of attracting the attentionof persons, i.e. has a superior eye-catching effect.

[0243] As will be seen from the foregoing description, according to the29th aspect of the invention, there is provided a hologram displayingsystem capable of displaying a superior image and having a goodeye-catching effect.

[0244] The photosensitive material used for fabricating the hologramelement is generally composed of photo-polymer. The portion of thephoto-polymer to which the laser beam is applied is crosslinked andformed with interference fringes.

[0245] Also, for a superior image to be displayed on the hologram screendescribed above, the interference fringes desirably remain in the samestate as immediately after fabrication (initial state).

[0246] The interference fringes, however, are liable to be deterioratedby heat.

[0247] Consider, for example, the case in which a hologram element isattached to a transparent support like window glass to make up ahologram screen. The difference in thermal expansion coefficient existsbetween the hologram element and the transparent support. When thehologram element and the transparent support are heated, therefore, athermal stress occurs between them. This thermal stress sometimes causesthe distortion of the photo-polymer making up the hologram element.

[0248] The distortion of the interference fringes causes a distorteddiffraction of the image beam, with the result that the image reproducedon the hologram screen is likely to develop a distortion.

[0249] Heat sources considered to cause this problem include the heat ofthe image beam itself, the hot air produced from the cooling fan or thelike installed on the projector, the direct sunlight in high-temperatureseasons such as the summer, and the heat reflected from the groundsurface.

[0250] With the hologram displaying system according to the 29th aspectof the invention, the hologram screen is installed under theabove-mentioned conditions.

[0251] The hologram screen thus is installed some distance off the floorand has a spatial margin with the floor surface. As a result, thehologram screen is prevented from being heated by the heat whichotherwise might stay around the hologram screen.

[0252] The hologram screen, if it has a height of less than 80 cm, isliable to be exposed to the heat radiated back from the ground surface.Also, the proximity to the floor surface often causes the heat to remaindue to the inefficient heat radiation.

[0253] In the case where the hologram screen has a height of more than180 cm, on the other hand, the image is not easily visible.

[0254] Especially a hologram screen used by being attached to the glassis desirably held between biaxial oriented PET films or the like havinga thermal expansion coefficient similar to that of glass (3 to 10×10⁻⁶cm/° C.) in order to alleviate the thermal effect efficiently.

[0255] With the hologram displaying system according to the 29th aspectof the invention, the projector can be installed either above or underthe hologram screen (embodiments C1, C2). It is also possible to arrangethe hologram displaying system at a position diagonally above or belowthe hologram screen.

[0256] In the case where the projector is arranged below the hologramscreen and the image beam is projected from under the hologram screen,the hologram screen should be located as high as possible. In the casewhere the projector is arranged above the hologram displaying system, incontrast, the hologram screen is desirably located as low as possible.In this way, the zero-order beam from the projector (the image beamprojected from the projector) is prevented from entering into the eyesof the viewer.

[0257] According to a 30th aspect of the invention, there is provided ahologram displaying system comprising a hologram screen and a projectorfor projecting the image beam on the hologram screen, wherein the centerheight of the hologram screen is 110 to 210 cm from the floor level.

[0258] Also, with the hologram displaying system according to the 30thaspect of the invention, as described above, the viewing angle of thehologram screen comes just in the range of the line of sight of theviewer and therefore a superior image can be displayed in the range ofthe viewer's field of view.

[0259] In this respect, the invention can display an image highlyappealing to the viewer. In other words, the system has a goodeye-catching effect.

[0260] As described above, according to the 30th aspect of theinvention, there is provided a hologram displaying system capable ofdisplaying a superior image and having a high eye-catching effect.

[0261] In the case where the center height is less than 110 cm, the lineof the viewer's sight is liable to depart from the viewing angle, andtherefore the image hue is deteriorated making the image not easilyvisible. In the case where the height is more than 210 cm, in contrast,the hologram screen is installed at a correspondingly high position andthe image is also liable to be not easily visible.

[0262] The reference floor level for measurement of the center height inthis example is also represented by the floor surface 311 on which theviewer 8 stands, as shown in FIG. 55.

[0263] Also, the fact that the hologram screen is installed under theabove-mentioned conditions prevents the heat from remaining around thehologram screen.

[0264] In the case where the center height is less than 110 cm, thehologram screen is exposed to the heat radiated back from the floorsurface and the heat is liable to stay around the hologram screen.

[0265] According to a 31st aspect of the invention, there is provided ahologram displaying system comprising a hologram screen and a projectorfor projecting the image beam on the hologram screen, wherein the angleof projection of the projector to the hologram screen is 20 to 50degrees.

[0266] With the hologram displaying system according to the 31st aspectin which the projection angle is set within the range mentioned above,the viewing angle of the hologram screen is just within the range of theviewer's line of sight. A superior image can thus be displayed withinthe range of the viewer's line of sight.

[0267] In this respect, the system according to the invention candisplay an image highly appealing to the viewer, i.e. it has a goodeye-catching effect.

[0268] In the case where the projection angle is less than 20 degreesthe zero-order beam from the projector intrudes the viewer's eyes and isliable to make normal observation of the image impossible.

[0269] In the case where the projection angle exceeds 50 degrees, incontrast, the trapezoidal distortion of the image projected on thehologram screen increases to such an extent that a normal image becomesdifficult to observe.

[0270] As shown in FIG. 34 described later, the projector is sometimesinstalled at a position diagonally above or below as well as just aboveor below the hologram screen for projecting the image beam.

[0271] It is shown in FIG. 43 that the projection angle of α indicatesthe state in which the projector is installed on the circumference of acircle constituting the bottom of a cone assumed to have an apex at thecenter of the hologram screen.

[0272] Specifically, as shown in FIG. 43, assume that image projectorsare installed at a position t1 above the hologram, at a position t2below the hologram screen, at a position t3 diagonally above thehologram screen and at a position t4 diagonally below the hologramscreen. The projection angle of all the projectors is the same and α.

[0273] As in a 32nd aspect of the invention, the hologram displayingsystem desirably comprises a trapezoidal distortion correctionmechanism.

[0274] There is thus provided a hologram displaying system capable ofdisplaying a correct image free of a trapezoidal distortion on thehologram screen and permitting the viewer to observe a correct image.

[0275] The trapezoidal distortion correction mechanism may include atrapezoidal distortion correction circuit capable of correcting theimage electrically or a correction device for correcting the imageoptically using a lens.

[0276] According to a 33rd aspect of the invention, the diagonal lengthof the hologram screen is desirably not less than 30 inches and theprojection distance of the image beam is desirably not less than 90 cm.

[0277] This permits the projector to be installed in a limited spacewhile at the same time securing an image size of not less than 30 incheswhich is sufficiently large to produce an eye-catching effect. Also,substantially all the projectors sold on the market can be used.

[0278] The diagonal length indicates the length of the diagonal line ofa substantially rectangular hologram screen. In the case where thediagonal length is less than 30 inches, the eye-catching effect isliable to be insufficient.

[0279] The upper limit of the diagonal length, though not specificallydefined, is a value that can secure the distance from the floor leveldescribed in each of the claims.

[0280] The projection distance is defined as the distance between thesurface of the hologram screen and the image beam projection unit of theprojector (such as the lens of the liquid crystal projector).

[0281] In the case where the projection distance of the image beam isshorter than 90 cm, the diagonal length of the image probably is lessthan 30 inches. At the same time, the projector projects the image ofitself on the hologram screen and undesirably becomes visible to theviewer.

[0282] The upper limit of the projection distance is desirably set to350 cm. In the case where this upper limit is exceeded, the installationspace increases to such an extent that the projector cannot be easilysuspended from a low ceiling. Even in the case where the projector isinstalled on the floor, a sufficient space may not be secured. Further,even when the image is focused by the zoom function of the projector,the image often overflows the hologram screen.

[0283] According to a 34th aspect of the invention, the relation y=ax+b(where x is the diagonal length in inches, y is the projection distancein cm, and a, b are coefficients depending on the projector involved) isdesirably satisfied between the diagonal length of the hologram screenand the projection distance.

[0284] As a result, the size of the hologram screen can be matched withthe performance of the projector, thereby saving the installation space.

[0285] For Projector TH-L392J of Matsushita Electric Industrial Co., forexample, a=4.6 and b=−23.7.

[0286] Generally, the coefficient a assumes a value of −20 to −30.

[0287] As shown in FIG. 39 described later, in the case where aplurality of hologram screens are arranged side by side and used as asingle large screen, the diagonal length of the combined large screen isemployed as the diagonal length L of the hologram screen underconsideration.

[0288] According to a 35th aspect of the invention, the hologram screenis desirably installed in an environment where the contrast (defined as(brightness of white image screen+background brightness+external beambrightness)/(brightness of black image screen+backgroundbrightness+external beam brightness)) is not less than 1.5. This securesan image appearance having a sufficient eye-catching effect.

[0289] In the case where the contrast is less than 1.5, the imageappearance is so inferior that a sufficient eye-catching effect may notbe secured. A more desirable upper limit of the contrast is 300. For acontrast higher than this value, the image becomes too bright and oftendifficult to view.

[0290] The brightness of white image screen is the brightness of thenormal white screen input on a personal computer, and the brightness ofblack image screen is the brightness of the black screen input on apersonal computer. Also, the background brightness is the brightness ofan object behind the hologram screen, and the external beam brightnessis the brightness of an object projected on the hologram screen.

[0291] For realizing the above-mentioned environment, a configuration asdescribed below is desirably provided for the hologram displayingsystem.

[0292] For example, the projector is desirably configured in such amanner that a sensor for detecting the brightness around the hologramscreen is operatively interlocked with means for adjusting the imagebrightness and the image size.

[0293] Also, as in the embodiment C7 described later, a polarizing filmor an antireflection film is desirably incorporated in the hologramscreen to reduce the background brightness and the external beambrightness for an improved contrast.

[0294] The hologram displaying system according to this invention isdesirably installed in such a position that the hologram screen is notexposed to sunlight directly. This arrangement can exclude the adverseeffect of heat while at the same time improving the contrast of theenvironment of the hologram screen to not less than 1.5 as describedabove.

[0295] If an antireflection film, a polarizing film or the like ismounted on the hologram screen as such a protective means like in theembodiment C7 described later, a normal image can be observed even at avery bright place under direct sunlight.

[0296] Also, a sunshade, a peak or a blind can be provided forprotection from direct sunlight.

[0297] According to a 36th aspect of the invention, the hologram screenis chamfered at the corners thereof, or the section of the hologram istapered.

[0298] As a result, the hologram screen is not easily removed.

[0299] As shown in the embodiment C1 described later, the hologramscreen installed on the window glass or the like is prevented fromcoming off at the time of cleaning the window.

[0300] The wording “the corners are chamfered” is indicative of the factthat what is called at least a corner R is formed. The corners of thehologram screen are thus formed as shown in FIGS. 37(a), 37(d) describedlater, for example.

[0301] The wording “the section is tapered” means configuring a hologramscreen into the state as shown in FIGS. 37(c), 37(d) described later,for example.

[0302] According to a 37th aspect of the invention, the hologram screenis desirably installed by covering with water (stretch).

[0303] This allows for a sufficient time before being dried, duringwhich the position of the hologram screen can be finely adjusted takingadvantage of the slidability of water.

[0304] Adhesives usable for the above-mentioned stretch include acrylicester copolymer, acrylic styrene copolymer, polyvinyl alcohol, polyvinylbutyral or the like, aqueous micromole, aqueous emulsion or the like,and an organic binder for plastic which becomes transparent when dried.

[0305] According to a 38th aspect of the invention, the projector isdesirably fixed at an inclination angle of 20 to 50 degrees to thehorizontal ceiling surface by a fixing jig.

[0306] As a result, the eyes of the viewer are protected from thezero-order beam of the image projector and the viewer can normallyobserve the image.

[0307] In the case where this angle is less than 20 degrees, thezero-order beam is liable to intrude the viewer's eyes. For theinclination angle of more than 50 degrees, on the other hand, the imageis often distorted excessively or an out-of-focus condition may develop.

[0308] The inclination angle of the projector to the horizontal ceilingsurface will be explained.

[0309] Consider a straight line perpendicular to the surface on whichthe hologram screen is installed. In the case where this straight lineis parallel to the ceiling surface (FIG. 34), the ceiling constitutesthe horizontal ceiling surface. The angle that the ceiling forms withthe projector is the inclination angle.

[0310] In the case where the straight line perpendicular to the surfaceon which the hologram screen is installed is not parallel to the surfaceof the ceiling (FIG. 56), on the other hand, the plane containing theparticular straight line constitutes the horizontal ceiling surface. Theangle that this horizontal ceiling surface forms with the projectorconstitutes the inclination angle.

[0311] The surface on which the hologram screen is installed is regardedas the plane containing the surface of the hologram screen in the casewhere the hologram screen is flat.

[0312] According to the 29th to 38th aspects of the invention, thehologram displaying system can also comprise various sensors whichproduces signals for controlling the operation of the projector. Thus, asystem is realized which is automatically activated whenever required.The various sensors referred to above include those for detecting thebrightness, weight, rain, humidity, temperature, odor, sunlight, etc.

[0313] On the other hand, a plurality of hologram screens can becombined side by side to construct a large-sized hologram screen. Inthis case, the image beam corrected in accordance with the properties ofeach hologram screen is projected, and thus an integrated image free ofthe sense of incompatibility as a whole can be observed.

[0314] The correction referred to above includes the adjustment of thehue, brightness, etc. of the image beam.

BRIEF DESCRIPTION OF THE DRAWINGS

[0315] Other objects and features of the present invention will bedescribed hereinafter in detail by way of preferred embodiments withreference to the accompanying drawings, in which:

[0316]FIG. 1 shows an image information displaying system according toan embodiment A1 of the present invention;

[0317]FIG. 2 is a plan view showing a viewing angle of a hologram screenof the embodiment A1;

[0318]FIG. 3 is a side view showing the viewing angle of the hologramscreen of the embodiment A1;

[0319]FIG. 4 is a side view showing an image information displayingsystem according to an embodiment A2 of the present invention;

[0320]FIG. 5 is a plan view showing the embodiment A2;

[0321]FIG. 6 shows an image information displaying system connected to acentral control unit according to an embodiment A3 of the presentinvention;

[0322]FIG. 7 shows an image information displaying system with a weightsensor according to an embodiment A4 of the present invention;

[0323]FIG. 8 shows an image information displaying system with anilluminance sensor according to an embodiment A5 of the presentinvention;

[0324]FIG. 9 explains a technique of manufacturing a hologram screen ofthe embodiment A5;

[0325]FIG. 10(a) is a sectional view showing a hologram screen with apolyester polarization film of the embodiment A5;

[0326]FIG. 10(b) is a sectional view showing a hologram screen with anantireflection film of the embodiment A5;

[0327]FIG. 11 shows an image information displaying system with ahologram screen having a shade according to the embodiment A5;

[0328]FIG. 12 shows an image information displaying system installed ina mobile body according to an embodiment A7 of the present invention;

[0329]FIG. 13 shows an installed state of a hologram screen of theembodiment A7;

[0330]FIG. 14 shows another installed state of the hologram screen ofthe embodiment A7;

[0331]FIG. 15 shows an arrangement of the system of the embodiment A7;and

[0332]FIG. 16 shows the system of the embodiment A7 with a projectorhaving a damping mechanism.

[0333]FIG. 17 is a diagram for explaining a configuration of an imageinformation displaying system according to an embodiment B1.

[0334]FIG. 18 is a plan view for explaining the viewing angle of ahologram screen of an image information displaying system according tothe embodiment B1.

[0335]FIG. 19 is a side view for explaining the viewing angle of ahologram screen of an image information displaying system according tothe embodiment B1.

[0336]FIG. 20 is a diagram for explaining a multiplicity of imageinformation displaying systems connected to a central control unitaccording to the embodiment B1.

[0337]FIG. 21 is a side view for explaining an image informationdisplaying system according to an embodiment B2.

[0338]FIG. 22 is a plan view for explaining an image informationdisplaying system according to the embodiment B2.

[0339]FIG. 23 is a diagram for explaining an image informationdisplaying system using a weight sensor according to the embodiment B3.

[0340]FIG. 24 is a diagram for explaining an image informationdisplaying system using a illuminance sensor according to the embodimentB4.

[0341]FIG. 25 is a diagram for explaining a method of fabricating ahologram screen according to the embodiment B4.

[0342]FIG. 26(a) is a sectional view for explaining a hologram screenhaving a polyester polarizing film according to the embodiment B4, and

[0343]FIG. 26(b) is a sectional view for explaining a hologram screenhaving an antireflection film according to the embodiment B4.

[0344]FIG. 27 is a diagram for explaining an image informationdisplaying system having a sunshade of a hologram screen according tothe embodiment B4.

[0345]FIG. 28 is a diagram for explaining an image informationdisplaying system mounted on a mobile body according to the embodimentB6.

[0346]FIG. 29 is a diagram for explaining a manner in which the displayunit of an image information displaying system is installed according tothe embodiment B6.

[0347]FIG. 30 is a diagram for explaining another manner in which thedisplay unit of an image information displaying system is installedaccording to the embodiment B6.

[0348]FIG. 31 is a diagram for explaining a configuration of an imageinformation displaying system according to the embodiment B6.

[0349]FIG. 32 is a diagram for explaining a configuration of an imageinformation displaying system having a vibration control mechanism of aradiation unit according to the embodiment B6.

[0350]FIG. 33(a) is a diagram for explaining the image that hasdeveloped a trapezoidal distortion according to the embodiment B7,

[0351]FIG. 33(b) is a diagram for explaining the image subjected touniform compressive complementary correction according to the embodimentB7, and

[0352]FIG. 33(c) is a diagram for explaining the image subjected totrapezoidal distortion correction according to the embodiment B7.

[0353]FIG. 34 is a side view for explaining a hologram displaying systemaccording to the embodiment C1.

[0354]FIG. 35 is a plan view for explaining a hologram displaying systemaccording to the embodiment C1.

[0355]FIG. 36 is a diagram for explaining the layout of a hologramdisplaying system according to the embodiment C.

[0356] FIGS. 37(a) and 37(b) are plan views of a hologram screen withthe corners thereof chamfered, and

[0357] FIGS. 37(c) and 37(d) are sectional views of a hologram screenhaving a tapered section according to the embodiment C1.

[0358] FIGS. 38(a) to 38(c) are diagrams for explaining a configurationemploying a plurality of hologram screens according to the embodimentC1.

[0359]FIG. 39 is a diagram for explaining the diagonal length of aplurality of hologram screens combined according to the embodiment C1.

[0360] FIGS. 40(a) and 40(b) are diagrams for explaining a hologramscreen bonded by an adhesive tape and a seal, respectively, according tothe embodiment C1.

[0361]FIG. 41 is a side view for explaining a hologram displaying systemaccording to the embodiment C2.

[0362]FIG. 42 is a plan view for explaining a hologram displaying systemaccording to the embodiment C2.

[0363]FIG. 43 is a diagram for explaining the positions at which thehologram screen and the projector can be installed when the projectionangle is α according to the embodiment C2.

[0364]FIG. 44 is a perspective view for explaining a hologram displayingsystem having two mirrors according to the embodiment C3.

[0365]FIG. 45 is a side view for explaining a hologram displaying systemso configured that a hologram screen and a projector are suspended fromthe ceiling according to the embodiment C4.

[0366]FIG. 46 is a diagram for explaining the configuration and theoperation of a hologram displaying system according to the embodimentC6.

[0367]FIG. 47 is a diagram for explaining the principle of a hologramdisplaying system according to the embodiment C6.

[0368]FIG. 48 is a diagram for explaining a method of fabrication of ahologram displaying system of transmission type according to the presentinvention.

[0369]FIG. 49 is a diagram for explaining a method of fabrication of ahologram displaying system of reflection type according to theinvention.

[0370]FIG. 50 is a diagram for explaining the configuration of ahologram displaying system according to the embodiment C7.

[0371] FIGS. 51(a) to 51(f) are diagrams for explaining various forms ofhologram screen according to the embodiment C8.

[0372] FIGS. 52(a) to 52(f) are diagrams for explaining various forms ofhologram screen according to the embodiment C8.

[0373] FIGS. 53(a) to 53(f) are diagrams for explaining various forms ofhologram screen according to the embodiment C8.

[0374]FIG. 54 is a diagram for explaining a hologram screen on which animage 100 is partially projected according to the embodiment C8.

[0375]FIG. 55 is a diagram for explaining a hologram displaying systeminstalled at a place in a showroom where the floor level of the showroomand the floor on which the viewer stands are different in heightaccording to the embodiment C9.

[0376]FIG. 56 is a diagram for explaining a hologram displaying systeminstalled in a showroom having a diagonal ceiling surface according tothe embodiment C9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0377] From FIG. 1 to FIG. 16, the same reference numeral represents thesame part. From FIG. 17 to FIG. 33, the same reference numeralrepresents the same part. From FIG. 34 to FIG. 56, the same referencenumeral represents the same part. Even if a reference numeral in thegroup of FIG. 1-FIG. 16 is the same as a reference numeral in the othergroup of FIG. 17-FIG. 33 or of FIG. 34-FIG. 56, the same referencenumeral does not always represent the same part.

[0378] Embodiment A1

[0379] FIGS. 1 to 3 show an image information displaying systemaccording to an embodiment A1 of the present invention.

[0380] The image information displaying system 1 has a transparentsupport 10, a hologram screen 11 attached to the support 10, and aprojector 12 for projecting image information onto the screen 11.

[0381] The system 1 also has a sensor 13 that senses a person 8 whoenters a viewing angle 15 of the screen 11, and a controller 14 forcontrolling the projector 12 according to signals from the sensor 13 sothat the projector 12 may project image information onto the screen 11.

[0382] The system 1 is installed in a showroom 20. The hologram screen11 is of a transmission type. The transparent support 10 on which thescreen 11 is attached is a glass window of the showroom 20. An exhibit21 is set behind the screen 11.

[0383] If no image information is displayed on the screen 11, viewerscan see the exhibit 21 through the screen 11.

[0384] The principle of the transmission-type hologram screen willbriefly be explained.

[0385] The hologram screen has a hologram element. A projector isinstalled behind the screen and projects image information onto thescreen. The image information forms a real image on the screen. Thescreen scatters and transmits the light of the real image, which is seenby viewers.

[0386] The sensor 13 is fixed to the ceiling 29 of the showroom 20. Theprojector 12 is fixed to an arm 126, which is fixed to the ceiling 29.The projector 12 has a movable lens 125. The sensor 13 is an infraredsensor. The projector 12 is a liquid crystal projector.

[0387] The controller 14 is arranged in a roof-space 290 and isconnected to the projector 12 and sensor 13. The controller 14 has aplayer having an optical disk that holds image information. The playeris connected to the projector 12 through a cable for transmitting imageinformation.

[0388] The viewing angle of the hologram screen 11 will be explained.

[0389]FIG. 2 is a plan view showing the system 1 in the showroom 20, andFIG. 3 is a side view showing the same.

[0390] The viewing angle 15 of the screen 11 has a sectorial area inwhich brightness is K0/2 or over. Here, K0 is the brightness of a frontcenter point G of the screen 11. The shape of the viewing angle 15 isactually conical.

[0391] The viewing angle will be explained in more detail.

[0392] The projector 12 emits an image information beam 17, whichspreads in a sectorial area and reaches the screen 11. A portion of thebeam 17 that hits an edge E of the screen 11 is scattered by andtransmitted through the edge E, to form a sector 161. Another portion ofthe beam 17 that hits another edge F of the screen 11 is scattered byand transmitted through the edge F, to form a sector 162. The sectors161 and 162 overlap to form a new sector that is the viewing angle 15.

[0393] Although the beam 17 is scattered in a sectorial area in FIGS. 2and 3 because the figures are plan views, it is actually scattered in aconical space. Accordingly, the viewing angle 15 is actually conical.

[0394] The viewing angle 15 and brightness K0 will be explained withreference to FIGS. 2 and 3.

[0395] The front center point G of the hologram screen 11 is thebrightest point of the screen 11 and has the brightness K0.

[0396] In each of FIGS. 2 and 3, the viewing angle 15 is a sectorialarea in which one can see image information displayed on the screen 11.The brightness of the screen 11 decreases in proportion to the distancetherefrom.

[0397] The operation of the first embodiment will be explained.

[0398] If the person 8 who walks in front of the showroom 20 enters theviewing angle 15, the sensor 13 senses it and sends a signal to thecontroller 14. In response to the signal, the controller 14 activatesthe player and projector 12. The player sends image information to theprojector 12, which projects the image information onto the screen 11.

[0399] The screen 11 is transparent and is attached to the support 10that is also transparent. Accordingly, the screen 11 attracts noattention of the person 8 if no image information is displayed on thescreen 11.

[0400] As soon as the person 8 enters the viewing angle 15, theprojector 12 is activated to suddenly display image information on theglass window, i.e., the support 10 which the person 8 considered avacant window.

[0401] As a result, the image information strongly attracts theattention of the person 8, thus providing a good eye-catching effect.

[0402] When the person 8 walks out of the viewing angle 15, the sensor13 senses it and sends a signal to the controller 14 to stop the playerand projector 12.

[0403] In this way, the projector 12 is activated only while the person8 is present in the viewing angle 15, to greatly reduce the powerconsumption and running costs of the system 1.

[0404] Shortening the operation time of the system 1 results inextending the service life thereof.

[0405] In this way, the image information displaying system of the firstembodiment provides an excellent eye-catching effect, reduces energyconsumption and running costs, and extends its own service life.

[0406] Although the hologram screen 11 of the first embodiment is of atransmission type, it may be of a reflection type.

[0407] The reflection-type hologram screen will briefly be explained.

[0408] A projector is arranged in front of the screen and projects imageinformation onto the screen. The image information forms a real image onthe screen. The real image is scattered and reflected by the screen tocatch the eyes of a viewer, and the viewer sees the real image.

[0409] A technique of manufacturing a hologram screen will be explained.A source beam is passed through a diffuser such as a ground glass toform an object beam, and at the same time, the source beam is used as itis as a reference beam. The object and reference beams form interferencefringes on a photosensitive material, which forms the hologram screen.The transmission-type hologram screen is made by irradiating thephotosensitive material with object and reference beams in the samedirection. The reflection-type hologram screen is made by irradiatingthe photosensitive material with object and reference beams in oppositedirections.

[0410] Each of the transmission- and reflection-type hologram screens isapplicable to the image information displaying system of the presentinvention.

[0411] Embodiment A2

[0412]FIGS. 4 and 5 show three image information displaying systems 31to 33 installed in a showroom 20 according to an embodiment A2 of thepresent invention.

[0413] The systems 31 to 33 consist of a transparent support 10, whichis a glass window, hologram screens 111 to 113 attached to the support10, and projectors 121 to 123 for projecting image information onto thescreens 111 to 113. The screens 111 to 113 are arranged side by side onthe support 10 along the walking direction of a person 8.

[0414] Each of the projectors 121 to 123 is mounted on a base 128, whichis placed on the floor. The systems 31 to 33 have a sensor (not shown)and a controller (not shown) connected to the projectors 121 to 123.

[0415] The hologram screens 111 to 113 have viewing angles 151 to 153,respectively.

[0416] The other parts of the second embodiment are the same as those ofthe first embodiment.

[0417] The operation of the second embodiment will be explained.

[0418] The person 8 walks along arrows shown in FIG. 5.

[0419] The person 8 enters the viewing angle 151. The sensor senses thatthe person 8 is at a position 81 and sends a signal to the controller.In response to the signal, the controller activates the projector 121,which projects image information onto the hologram screen 111.

[0420] The person 8 walks out of the viewing angle 151 and into theviewing angle 152 to reach a position 82. The sensor senses this andsends a signal to the controller. In response to the signal, thecontroller stops the projector 121 and activates the projector 122,which projects image information onto the hologram screen 112.

[0421] The person 8 walks out of the viewing angle 152 and into theviewing angle 153 to reach a position 83. The sensor senses this andsends a signal to the controller. In response to the signal, thecontroller stops the projector 122 and activates the projector 123,which projects image information onto the hologram screen 113.

[0422] Thereafter, the person 8 walks out of the viewing angle 153. Thesensor senses this and sends a signal to the controller. In response tothe signal, the controller stops the projector 123.

[0423] In this way, the systems 31 to 33 display image informationaccording to the movement of the person 8. Namely, the systems 31 to 33provide a dynamic effect that image information appears and disappearsin synchronization with the movement of the person 8.

[0424] Accordingly, the systems 31 and 33 easily attract viewers'attention, thereby providing a good eye-catching effect.

[0425] The projectors 121 to 123 may consecutively provide a series ofimage information such that the projector 122 displays a continuation ofimage information displayed by the projector 121. However, they mayprovide different image information.

[0426] Embodiment A3

[0427]FIG. 6 shows image information displaying systems centrallycontrolled by a central control unit according to an embodiment A3 ofthe present invention.

[0428] The image information displaying systems 1 are connected to andcontrolled by the central control unit 30 through communicationcircuits. The central control unit 30 may be a large computer, aworkstation, etc.

[0429] The communication circuits for connecting the systems 1 to thecentral control unit 30 will be explained.

[0430] The central control unit 30 is connected to a relay 31 through acircuit 310 using optical fiber cables. The relay 31 may be a controllerfor distributing CATV programs. The relay 31 is connected to each imageinformation displaying system 1 through a CATV circuit 311.

[0431] In this way, the central control unit 30 is connected to eachsystem 1 through a public circuit. For example, the central control unit30 is connected to a public circuit 32 through a circuit 320, and thepublic circuit 32 is connected to each system 1 through a privatenetwork 35. The circuit 320 may be a public circuit. The public circuit32 and private network 35 are voice transmitting telephone circuitswhich may be analog or digital.

[0432] The central control unit 30 can be connected to a communicationsatellite 33 through a radio circuit 330. The satellite 33 is connectedto each system 1 through a satellite broadcasting radio circuit 331.

[0433] The other parts of the third embodiment are the same as those ofthe first embodiment.

[0434] Each image information displaying system 1 has a sensor. Whenpeople enter a viewing angle of a hologram screen of the system 1, thesensor senses it and sends a signal to a controller of the system 1. Inresponse to the signal, the controller sends a request of transmittingimage information to the central control unit 30 through the circuit311, relay 31, and circuit 310, or through the private network 35,public circuit 32, and circuit 320, or through the circuit 331,satellite 33, and circuit 330. In response to the request, the centralcontrol unit 30 transmits image information to the system 1.

[0435] Upon receiving the image information, the controller of thesystem 1 in question activates a projector thereof to project the imageinformation onto the hologram screen to display the image information.

[0436] If the people go out of the viewing angle, the sensor senses itand sends a signal to the controller. In response to the signal, thecontroller stops the projector and sends a request for stopping theimage information to the central control unit 30. Upon receiving therequest, the central control unit 30 stops sending the imageinformation.

[0437] In this way, the central control unit 30 centrally controls theimage information displaying systems 1, to save manpower and reducemanaging costs.

[0438] Embodiment A4

[0439]FIG. 7 shows an image information displaying system with a weightsensor according to an embodiment A4 of the present invention. Theweight sensor senses a person entering a viewing angle of a hologramscreen 11.

[0440] The system 1 has a transparent support 10, the hologram screen 11attached to the support 10, a projector 12, and a controller 14. Thesystem is installed in a showroom 20.

[0441] The weight sensor 139 is embedded in the floor 209 of theshowroom 20. A range of the weight sensor 139 of sensing weight is setto be equivalent to the viewing angle of the hologram screen 11.

[0442] The other parts and operation of the fourth embodiment are thesame as those of the first embodiment.

[0443] The controller 14 may have a timer to automatically start andstop the projector 12 according to time bands.

[0444] The system 1 may have a touch switch so that a person 8 mayfreely start and stop the projector 12.

[0445] Embodiment A5

[0446] FIGS. 8 to 11 show an image information displaying system with anilluminance sensor according to an embodiment A5 of the presentinvention. The illuminance sensor measures illuminance in a viewingangle of a hologram screen 11.

[0447] In FIG. 8, the system 1 has a transparent support 10, thehologram screen 11 attached to the support 10, a projector 12 forprojecting image information onto the screen 11, illuminance sensors 131and 132 for sensing ambient conditions in the viewing angle of thescreen 11, and a controller 14 for controlling the quantity of a beam171 emitted from the projector 12 according to signals from the sensors131 and 132.

[0448] The system 1 is installed between a room light 208 of a showroom20 and the sun 49 in the outside 40 of the showroom 20. The support 10is a glass window of the showroom 20 facing the outside 40.

[0449] The sensor 131 is positioned in the viewing angle in the outside40, and the sensor 132 is positioned in the viewing angle in theshowroom 20. The hologram screen 11 is of a transmission type.

[0450]FIG. 9 shows a technique of manufacturing the hologram screen 11.

[0451] A laser source 51 emits a coherent beam 61, which is reflected bya mirror 52 and is divided by a half-mirror 53 into a beam 62 for makingan object beam 621 and a beam 63 for making a reference beam 631. Thebeam 62 is reflected by a mirror 541 and is passed through an objectlens 542 and an off-axis parabolic mirror 543, to form a parallel beam.The parallel beam is passed through a diffuser 56 to form the objectbeam 621, which is made incident to a photosensitive material 58 througha half-mirror 57.

[0452] The other beam 63 from the half-mirror 53 is reflected by mirrors551 and 552 and is passed through an object lens 553 to form a divergentbeam. The divergent beam is passed through the half mirror 57 to formthe reference beam 631, which is made incident to the photosensitivematerial 58.

[0453] As a result, the diffuser 56 is recorded on the photosensitivematerial 58, which serves as the transmission-type hologram screen 11.

[0454] When the projector 12 emits a beam 171 (FIG. 8) in the samedirection as the reference beam 631 (FIG. 9) onto the screen 11, thebeam 171 is transmitted through the screen 11 to form a diffracted beam170, which is equivalent to a diffused beam provided by the diffuser 56.

[0455] Instead of the hologram screen formed by the technique mentionedabove, a transparent base material such as ANGLE 21 of Nippon Itagarasuor LUMISTY of Sumitomo Kagaku Kogyo having a visual-field selectingfunction may be used as a screen.

[0456] FIGS. 10(a) and 10(b) show each a hologram screen 11 attached toa transparent support 10 with a polyester film 102 being interposedbetween them. These elements are bonded to one another with transparentadhesives 101.

[0457] In FIG. 10(a), a polyester polarization film 103 having a hardcoat 104 is attached as an outermost layer of the hologram screen 11with a transparent adhesive 101.

[0458] The hard coat 104 protects the hologram screen 11 from scratcheswhen the screen 11 is cleaned. To provide this function, the hard coat104 must have a pencil hardness of 1H or more.

[0459] The polyester film 102 is 140 micrometers thick, and thepolyester polarization film 103 is 90 micrometers thick.

[0460] In FIG. 10(b), a polyester film 102 having an antireflection film105 and a hard coat 104 is attached as an outermost layer of thehologram screen 11 with a transparent adhesive 101.

[0461] If the hard coat 104 is arranged outside the antireflection film105, scratch resistance will improve but an antireflection effect willdisappear. Accordingly, the hard coat 104 must be arranged under theantireflection film 105. The antireflection film 105 provides an effectof reducing noise light due to interface reflection at the back of thehologram screen An antireflection film may also be arranged for thestructure of FIG. 10A, as an outermost layer of the polyesterpolarization film 103 having the hard coat 104.

[0462] In each of FIGS. 10A and 10B, an antifouling film may be arrangedoutside the antireflection film 105.

[0463] The operation of the fifth embodiment will be explained.

[0464] In FIG. 8, a viewer 8 observes image information displayed on thehologram screen 11. The viewer 8 receives light 482 from a background 48behind the viewer 8 reflected by the screen 11, and light 211 from anexhibit 21 through the screen 11. The light 482 and 211 is noise lightthat interferes with the image information displayed on the screen 11.

[0465] The illuminance sensor 131 is arranged in the viewing angle ofthe screen 11 in the outside 40. The illuminance sensor 132 is arrangedinside the showroom 20. These sensors 131 and 132 detect illuminance inthe outside 40 and in the showroom 20.

[0466] The controller 14 receives signals from the sensors 131 and 132.If the illuminance from both the sensors 131 and 132 is high, thecontroller 14 increases the quantity of light emitted from the projector12, to increase the brightness of images displayed on the screen 11.This results in making the noise light inconspicuous and improving thevisibility of the images.

[0467] If the sensors 131 and 132 detect low illuminance, the quantityof light emitted from the projector 12 will be relatively high. In thiscase, halation will occur. Then, the controller 14 decreases thequantity of light emitted from the projector 12 to improve thevisibility of images displayed on the screen 11.

[0468] If the sensors 131 and 132 detect illuminance that is excessivelyhigh to cause noise light that is uncontrollable even by maximizing thequantity of light emitted from the projector 12, the controller 14 maystop the projector 12.

[0469] In this way, the fifth embodiment is capable of optimizing thebrightness of images projected from the projector 12 or stopping theprojector 12 in response to ambient conditions in the viewing angle ofthe hologram screen 11.

[0470] Instead of adjusting the quantity of light emitted from theprojector 12, it is possible to adjust the area of light emitted fromthe projector 12 to adjust the brightness of images displayed on thehologram screen 11. This is possible because the brightness of an imageis in inverse proportion to the area of light that forms the image. Theadjustment of a light emitting area is done by using anenlargement-contraction mechanism for adjusting a lens position of theprojector 12.

[0471] Some image information has sufficient visibility even in a brightenvironment. In this case, image information that is hard to see underbright circumstances may be switched to another that is easy to see evenunder bright circumstances, if surrounding brightness is too high,thereby securing an eye-catching effect.

[0472] The illuminance sensors 131 and 132 may be brightness sensors tomeasure the brightness of the background 48 and exhibit 21.

[0473] As shown in FIG. 11, it is possible to arrange an illuminancesensor 135 oriented toward the hologram screen 11, to measure theilluminance of direct sunlight 490 from the sun 49. If the measuredilluminance is above a predetermined level, a shade 45 is driven toblock the direct sunlight 490.

[0474] The shade 45 may be a visor, a blind, a curtain, etc.

[0475] Embodiment A6

[0476] An image information displaying system according to an embodimentA6 of the present invention has a speaker for providing audioinformation.

[0477] Similar to the embodiment A1, the system of the sixth embodimentconsists of a transparent support, a hologram screen attached to thesupport, a projector for projecting image information onto the screen, avolume sensor for sensing the volume of sound in a viewing angle of thescreen, and a controller for controlling the projector and speaker inresponse to signals from the sensor.

[0478] In response to a sound volume detected by the volume sensor, thecontroller starts and stops the projector and adjusts the volume of thespeaker.

[0479] If the volume sensor senses sounds greater than a predeterminedlevel in the viewing angle of the screen, the controller determines thatpeople are present in or around the viewing angle and activates theprojector and speaker.

[0480] If the volume sensor senses no sound greater than thepredetermined level in the viewing angle, the controller determines thatthere are no people in and around the viewing angle and stops theprojector and speaker.

[0481] If the volume sensor senses noise larger than a predeterminedlevel, the controller increases the volume of the speaker so that peoplein the viewing angle may clearly hear audio information from thespeaker.

[0482] If the volume sensor senses noise smaller than the predeterminedlevel, the controller determines that the inside of the viewing angle isquiet and reduces the volume of the speaker so that people in theviewing angle may not receive unpleasantly loud audio information.

[0483] The other parts of the sixth embodiment are the same as those ofthe embodiment A1.

[0484] The system of the embodiment A6 is capable of providing audioinformation as well as image information and adjusting the volume ofaudio information in the viewing angle to a proper level, therebyimproving an eye-catching effect.

[0485] To easily detect a sound volume in the viewing angle, the volumesensor may have a sound collecting reflector, or may be a directionalvolume sensor.

[0486] Embodiment A7

[0487] FIGS. 12 to 16 show an image information displaying systeminstalled in a mobile body and, in particular, in a car according to anembodiment A7 of the present invention.

[0488] In FIGS. 12 and 13, a display unit 100 consists of a transparentsupport 10 and a hologram screen 11. The display unit 100 is attached toa suspender 70, which is attached to the ceiling of the car 7 and ispositioned between a driver's seat 71 and an assistant's seat 72, sothat a passenger 8 in a rear seat 73 may see image information on thescreen 11.

[0489] In FIG. 12, the image information displaying system 1 also has avibration sensor 133 and a controller 14. In response to signals fromthe vibration sensor 133, the controller 14 corrects a blur of imageinformation due to the vibration of the car 7.

[0490] The details of this arrangement will be explained with referenceto FIG. 15.

[0491] A signal from the vibration sensor 133 is supplied to an electriccorrector of the controller 14. An image source 120 such as a video decksupplies image information to a projector 12. The electric correctorcorrects the image information held in the projector 12 according to thesignal from the vibration sensor 133, and the projector 12 projects thecorrected image information onto the display unit 100.

[0492] The other parts of the embodiment A7 are the same as those of theembodiment A1.

[0493] The system 1 is mounted on the car 7 and, therefore, imageinformation to be seen by the passenger 8 will be blurred during thedriving of the car 7 if no measure against vibration is taken. Theseventh embodiment corrects image information according to signals fromthe vibration sensor 133 and projects the corrected image informationfrom the projector 12, so that the passenger 8 may see the correctedimage information without a blur.

[0494] The other operations and effects of the embodiment A7 are thesame as those of the embodiment A1.

[0495]FIG. 16 shows a modification of the embodiment A7.

[0496] In response to signals from the vibration sensor 133, thecontroller 14 suppresses the vibration of the projector 12 caused by thevibration of the car 7.

[0497] For this purpose, the modification employs a damping mechanism149 for the projector 12. Signals from the vibration sensor 133 aresupplied to the controller 14, which controls the damping mechanism 149accordingly. Image information is supplied from the image source 120 tothe projector 12. According to signals from the vibration sensor 133,the controller 14 activates the damping mechanism 149, to cancel theinfluence of the vibration of the car 7 on the projector 12.

[0498] This modification is capable of displaying image informationwithout a blur.

[0499] The display unit 100 of the embodiment A7 may be embedded in theback of the driver's seat 71 as shown in FIG. 14.

[0500] Embodiment B1

[0501] An image information displaying system according to theembodiment B1 of the invention will be explained with reference to FIGS.17 to 20.

[0502] As shown in FIG. 17, the image information displaying system 1according to this embodiment comprises a transparent support 10, ahologram screen 11 attached to the transparent support 10, and aradiation unit 12 for radiating image information on the hologram screen11.

[0503] As shown in FIGS. 18, 19, the image information displaying system1 further comprises a sensor 13 for detecting the entry of a viewer 8into a viewing angle 15 of the hologram screen 11, and a radiationcontrol unit 14 adapted to control the radiation unit 12 in such amanner as to radiate the image information on the hologram screen 11based on the signal from the sensor 13.

[0504]FIG. 17 shows a showroom 20 in which the image informationdisplaying system 1 according to this embodiment is installed. Thehologram screen 11 is of transmission type. The transparent support 10attached to the hologram screen 11 is the window glass of the showroom20. A commodity 21 is exhibited behind the hologram screen 11.

[0505] While the image information is not on display, the exhibitedcommodity 21 can be viewed through the hologram screen 11.

[0506] The principle of the hologram screen of transmission type will bebriefly explained.

[0507] The radiation unit is arranged on the back of the screen(hologram screen) including a hologram element, and the imageinformation is radiated from the radiation unit. This image informationis focused thereby to form a real image on the hologram screen. The beamtransmitted by scattering from this real image enters the eyes of theviewer so that the viewer can view the real image with his own eyes.

[0508] The sensor 13 is fixed on a ceiling 29 outside the showroom 20.The radiation unit 12 is fixed by means of an arm 126 on the ceiling 29inside the showroom 20. A lens portion 125 for radiating the imageinformation from the radiation unit 12 is movably configured. The sensor13 is an infrared sensor. The radiation unit 12 is a liquid crystalprojector.

[0509] The radiation control unit 14 is arranged in the space 290 abovethe ceiling of the showroom 20. The radiation control unit 14 isconnected to both the sensor 13 and the radiation unit 12.

[0510] The viewing angle of the hologram screen 11 will be explained.

[0511]FIG. 18 shows the showroom 20 and the image information displayingsystem 1 as viewed from above (plan view), and FIG. 19 shows themsideways (side view).

[0512] The viewing angle 15 of the hologram screen 11 is in the range ofa fan-shaped or sectorial area described in FIG. 18. Within this range,the brightness is not less than K0/4, where K0 is the brightness at thecenter front G of the hologram screen 11. The viewing angle is in theshape of a cone.

[0513] The viewing angle will be explained in detail.

[0514] In FIG. 18, the radiation beam 17 (containing the imageinformation) issued from the radiation unit 12 reaches the hologramscreen 11 while fanning out. The radiation beam 17 that has impinged onan end portion E of the hologram screen 11 is transmitted by scatteringand proceeds to fan out. The sectorial area thus formed is designated byreference numeral 161. The sectorial area formed by the beam impingingon the other end portion F of the hologram screen 11 is designated bynumeral 162. A new sectorial area formed by the portions overlapped bythe sectorial areas 161, 162 constitutes the viewing angle 15.

[0515] Similarly in FIG. 19, the radiation beam 17 that has reached anend portion H of the hologram screen 11 is transmitted by scatteringwhile expanding in the shape of a fan 163. In the case where theradiation beam 17 reaches an end portion I, on the other hand, it fansout in the fan shape 164. A new sectorial area formed by the overlappedportions of the sectorial areas 163, 164 makes up the viewing angle 15.

[0516] The foregoing description is made with reference to the planviews 18, 19. Therefore, the radiation beam 17 is assumed to expand inthe shape of a fan. Actually, however, it proceeds to diffuse into thespace and therefore the viewing angle 15 assumes a conical shape.

[0517] The brightness K0 and the viewing angle will be described morespecifically with reference to FIGS. 18 and 19.

[0518] In FIGS. 18 and 19, a point G is the one at the center front ofthe hologram screen 11, where the brightness is given as K0. The point Gis the brightest point on the hologram screen 11.

[0519] In FIGS. 18 and 19, the viewing angle 15 represents a sectorialportion as shown. Within this viewing angle 15, the image informationprojected on the hologram screen 1 is visible. The brightness of thehologram screen 11 decreases with the distance from the center point G.

[0520] The image information displaying system 1 was described above.

[0521] Now, an explanation will be given of the central control unit 30configured to control the image information displaying system 1.

[0522] As shown in FIG. 20, the image information displaying systems 1are controlled by the central control unit 30 including a mainframecomputer or various work stations connected through variouscommunication lines.

[0523] The communication line connecting the central control unit 30 andeach image information displaying system 1 will be explained.

[0524] As shown in FIG. 20, the central control unit 30 and a relay 31are connected by a line 310 made of an optical fiber cable. The relay 31also functions a controller for CATV program distribution. The relay 31and various image information displaying systems 1 are connected to eachother by CATV lines 311.

[0525] As shown in FIG. 20, the central control unit 30 and each imageinformation displaying system 1 are connected by the telephone line. Inthis case, the central control unit 30 is connected to the telephonecircuit 32 through a line 320 and further from the telephone circuit 32through extension networks 35 to each image information displayingsystem 1. The line 320 can also be the telephone line. The telephonecircuit 32 and the extension networks 35 are voice transmission (analogor digital) lines used for telephone.

[0526] As shown in FIG. 20, the central control unit 30 is connected bya radio channel 330 to a broadcasting communication satellite 33, which,in turn, is connected to each image information displaying system 1using broadcast satellite lines 331.

[0527] Now, an explanation will be given of the operation of the imageinformation displaying systems 1 and the central control unit 30.

[0528] As shown in FIG. 17, in each image information displaying system1, the sensor 13 detects the entry of the viewer into the viewing angle15 and sends a corresponding signal to the radiation control unit 14.Upon receipt of this signal, the radiation control unit 14 gives arequest to the central control unit 30 to distribute the imageinformation through the lines 311, the relay 31 and the line 310, orthrough the extension networks 35, the telephone circuit 32 and the line320 or through the lines 331, the communication satellite 33 and theline 330. The central control unit 30 that has received this requestsends out the image information to each image information displayingsystem 1.

[0529] The radiation control unit 14 that has received the imageinformation activates the radiation unit 12 while at the same timesending out the received image information to the radiation unit 12. Inthis way, the radiation unit 12 radiates the image information on thehologram screen 11, so that the image information is displayed on thehologram screen 11.

[0530] After that, the sensor 13 of each image information displayingsystem 1 detects that the viewer 8 has left the viewing angle 15. Inresponse to the signal from the sensor 13, the radiation control unit 14deactivates the radiation unit 12 while at the same time requesting thecentral control unit 30 to stop the image information. The centralcontrol unit 30 that has received this request stops sending out theimage information.

[0531] As described above, all the image information displaying systems1 can be controlled and operated collectively by the central controlunit 30, and therefore both energy and labor are saved. Also, the imageinformation are managed collectively by the central control unit 30 fora reduced management cost.

[0532] The operation and effects of the image information displayingsystem 1 according to this embodiment will be explained.

[0533] The sensor 13 detects the viewer 8 passing in front of theshowroom 20 and into the viewing angle 15, and sends out a signal to theradiation control unit 14. In response to this signal, the radiationcontrol unit 14 activates the reproduction unit and the radiation unit12, and sends out the image information to the radiation unit 12. Theimage information is displayed on the hologram screen 11.

[0534] The hologram screen 11 is transparent and attached on the windowglass making up a transparent support 10. As long as the imageinformation is not displayed, therefore, the hologram screen 1 is soinconspicuous that it hardly attracts the attention of the viewer 8.

[0535] Once the viewer 8 enters the viewing angle 15, however, theradiation unit 12 is activated and the image information is suddenlydisplayed on the window glass (transparent support 10) which has thusfar been considered empty by the viewer 8.

[0536] As a result, the attention and interest of the viewer 8 areconsiderably attracted to the image information. In other words, a goodeye-catching effect is produced.

[0537] After that, the viewer 8 leaves the viewing angle 15. This isdetected by the sensor 13 which sends a signal to the radiation controlunit 14. The radiation control unit 14 deactivates the reproduction unitand the radiation unit 12.

[0538] Thus, the radiation unit 12 operates only during the period whenthe viewer 8 exists within the viewing angle 15, and the operation timeof the radiation unit 12 can be reduced remarkably as compared with thecase where the image information is constantly supplied. In this way,the power consumption of the system is reduced for a lower running cost.

[0539] Since the operation time of the system can be shortened, theservice life of the system is lengthened.

[0540] As described above, according to this embodiment, an imageinformation displaying system is provided which is superior in theeye-catching effect, low in energy consumption and running cost, andlong in service life.

[0541] Although the present embodiment uses the hologram screen oftransmission type, the reflection-type hologram can alternatively beused.

[0542] The principle of the reflection-type hologram screen will bebriefly described.

[0543] The radiation unit is arranged in front of the hologram screen,and the image information is radiated from the radiation unit. Thisimage information is focused on the hologram screen to form a real imagethereon. The beam reflected from this real image by scattering entersthe eyes of the viewer so that the viewer can grasp the real image.

[0544] Also, the hologram screen can be so configured that interferencefringes are formed in a photosensitive material by a beam diffusedthrough a light diffuser such as ground glass as an object beam and by anon-diffused beam as a reference beam. The reference beam and the objectbeam are radiated from the same direction for the transmission-typehologram screen, while they are radiated from opposite directions forthe reflection-type hologram screen.

[0545] In this case, an image information displaying system similar tothe present embodiment can be produced.

[0546] Embodiment B2

[0547] This embodiment refers to a configuration example in which threeimage information displaying systems 31 to 33 are installed in ashowroom 20 as shown in FIGS. 21 and 22.

[0548] As shown in FIGS. 21, 22, the three image information displayingsystems 31 to 33 according to this embodiment include a transparentsupport 10 constituting window glass, three hologram screens 111 to 113attached to the transparent support 10 and three radiation units 121 to123 for radiating the image information on the hologram screens 111 to113, respectively. The hologram screens 111 to 113 are attached injuxtaposition horizontally (along the direction in which the viewer 8moves) with respect to the transparent support 10.

[0549] As shown in FIG. 21, the radiation units 121 to 123 are mountedon a rest 128 on the floor. Also, a sensor and a radiation control unit,though not shown, are connected to the radiation units 121 to 123.

[0550] The reference numerals 151 to 153 designate viewing anglescorresponding to the hologram screens 111 to 113, respectively.

[0551] The other component parts are similar to the corresponding ones,respectively, in the embodiment B1.

[0552] The operation and effects of this embodiment will be explained.

[0553] As shown in FIG. 22, the viewer 8 moves downward from above inthe drawing.

[0554] The viewer 8 enters the viewing angle 151. The sensor detectsthat the viewer 8 has reached the position designated by referencenumeral 81 and sends a signal to the radiation control unit. In responseto this signal, the radiation control unit activates the radiation unit121 thereby to radiate the image information on the hologram screen 111.

[0555] The viewer 8 continues to move and leaves the viewing angle 151,and then enters the viewing angle 152 reaching the position 82. This isdetected by a sensor and a signal is sent to the radiation control unit.As a result, the radiation control unit deactivates the radiation unit121 and activates the radiation unit 122, thereby radiating the imageinformation on the hologram screen 112.

[0556] The viewer 8 further moves, leaves the viewing angle 152 andenters the viewing angle 153, reaching the position 83. This movement isdetected by a sensor which sends a signal to the radiation control unit.In response to this signal, the radiation control unit deactivates theradiation unit 122 and activates the radiation unit 123. Then, the imageinformation is radiated on the hologram screen 113.

[0557] After that, the viewer 8 leaves the viewing angle 153. A sensordetects this movement, and sends a signal to the radiation control unit,which in turn deactivates the radiation unit 123.

[0558] In the above-described manner, the image information displayingsystems 31 to 33 according to this embodiment can display the imageinformation at positions interlocked with the movement of the viewer 8.As a result, a dynamic effect is produced in which the image informationappears and disappears with the movement of the viewer 8.

[0559] The image information displaying systems 31 to 33 according tothis embodiment can thus readily attract the attention and interest ofthe viewers and produce a good eye-catching effect.

[0560] The image information radiated from the radiation units 121 to123 and displayed can be the same one (such as when the continuation ofthe image radiated by the radiation unit 121 is radiated also by theradiation unit 122) or different ones.

[0561] Embodiment B3

[0562] This embodiment refers to an image information displaying systemusing a weight sensor for detecting the entry of the viewer into theviewing angle.

[0563] As shown in FIG. 23, the image information displaying system 1according to this embodiment, like the first embodiment, includes thetransparent support 10, the hologram screen 11, the radiation unit 12and the radiation control unit 14 and is installed in a showroom 20.

[0564] A weight sensor 139 capable of detecting the weight is buried inthe front floor 209 of the showroom 20. The range in which the weightsensor 139 can detect the weight is set as an area where the viewingangle described above is projected on the floor surface 209.

[0565] The remaining parts of the configuration are similar to thecorresponding parts of the first embodiment and have similar functionsand effects to the corresponding parts of the embodiment B1.

[0566] According to this embodiment, a timer can be included in theradiation control unit 14 for automatically activating and deactivatingthe radiation unit 12 in desired time zones.

[0567] Also, a touch switch or the like can be provided enabling theviewer 8 to activate and deactivate the radiation unit 12 freely.

[0568] Embodiment B4

[0569] This embodiment refers to an image information displaying systemusing an illuminance sensor as the above-mentioned sensor capable ofdetecting the light amount within the viewing angle, as shown in FIGS.24 to 27.

[0570] As shown in FIG. 24, the image information displaying system 1according to this embodiment includes the transparent support 10, thehologram screen 11 attached to the transparent support 10, the radiationunit 12 for radiating the image information, illuminance sensors 131,132 for detecting the ambient condition within the viewing angle of thehologram screen 11, and the radiation control unit 14 capable ofadjusting the amount of the radiation beam 17 produced from theradiation unit 12 in accordance with the signals from the illuminancesensors 131, 132.

[0571] The image information displaying system 1 is installed betweenthe showroom 20 radiated by a room lamp 208 and an outdoor environment40 radiated by the sun 49. In other words, the window glass partitioningthe showroom 20 and the outdoor environment 40 makes up the transparentsupport 10.

[0572] The illuminance sensor 131 is installed within the viewing angleon the outdoor side of the transparent support 10. The illuminancesensor 132, on the other hand, is installed in the showroom 20.

[0573] The hologram screen 11 is of transmission type.

[0574] Now, a method of fabricating the hologram screen 11 will beexplained with reference to FIG. 9.

[0575] The light path of the coherent beam 61 emitted from a laser beamsource 51 is bent by a mirror 52, and split into the light path for anobject beam 621 and the light path for the reference beam 631 by a halfmirror 53. The beam 62 emitted from one of the light paths (to the leftin the drawing) is converted into parallel beams through a mirror 541,an objective lens 542 and an off-axis paraboloidal mirror 543, afterwhich it passes through a tabular diffuser 56 to form an object beam621. The beam further enters a photosensitive material 58 through a halfmirror 57.

[0576] The other beam 63 that has left the half mirror 53, on the otherhand, is converted into a divergent beam by an objective lens 553through mirrors 551, 552, and then enters the photosensitive material 58through the half mirror 57 as a reference beam 631.

[0577] As a result, the photosensitive material 58 is formed with atransmission-type hologram having the diffuser 56 recorded therein. Thisconstitutes the hologram screen 11 according to this embodiment.

[0578] The hologram screen 11 thus obtained is irradiated with aradiation beam 171 using the radiation unit 12 from the direction of thereference beam 631 in FIG. 9. Then, the diffracted beam 172 that hasbeen transmitted through the hologram screen 11 can make the same beamas the beam diffused by the diffuser 56.

[0579] The hologram screen that can be fabricated by the above-mentionedfabrication method can be replaced by a screen having a transparentsupport having the function of selecting the field of view (for example,Angle 21 of Nippon Sheet Glass Co., Ltd., or Lumistay of SumitomoChemical Co., Ltd.).

[0580] As shown in FIGS. 26(a), 26(b), the hologram screen 11 and thetransparent support 10 are bonded to each other using a transparentadhesive 101 through a polyester film 102.

[0581] Further, as shown in FIG. 26(a), a polyester polarizing film 103with a hard coat 104 can be bonded to the outermost layer of thehologram screen 11 by the transparent adhesive 101.

[0582] The provision of the hard coat 104 can prevent the hologramscreen 11 from being scratched at the time of cleaning (the scratchresistance is improved). Also, the hard coat 104 is required to have atleast 1H of pencil hardness for achieving the above-mentioned object.

[0583] The polyester films 102 are 140 μm thick, and the polyesterpolarizing film 103 is 90 μm thick.

[0584] Also, FIG. 26(b) shows a configuration in which the polyesterfilm 102 with the hard coat 104 and the antireflection film 105 areattached to the outermost layer of the hologram screen 11 using thetransparent adhesive 101.

[0585] The scratch resistance would be improved by attaching the hardcoat 104 to the exterior of the antireflection film 105. In order toavoid the resulting loss of the antireflection effect, however, it isnecessary to attach the hard coat 104 on the inside of theantireflection film 105. The antireflection film 105 has the effect ofreducing the noise light caused by the reflection at the interface onthe back of the hologram screen 11.

[0586] Also, the antireflection film 105 can be attached to theoutermost layer of the polyester polarizing film 103 with the hard coat104 in FIG. 26(a).

[0587] Apart from FIGS. 26(a), 26(b), an antifouling film capable ofreducing the fouling can be attached on the outside of theantireflection film 105.

[0588] The operation and effects of this embodiment will be explained.

[0589] As shown in FIG. 24, consider the image information radiated onthe hologram screen 11. The noise light other than the beam constitutingthe image information is observed from the two beams including a beam481 projected on the background 48 of the viewer on the front and backsides of the hologram screen 11 and a beam 211 from the exhibitedcommodity 21 constituting the background on the back side of thehologram screen 11.

[0590] In this embodiment, the illuminance sensor 131 is installedwithin the viewing angle on the outdoor environment 40 side of thetransparent support 10. The illuminance sensor 132, on the other hand,is installed within the showroom 20. These two illuminance sensors 131,132 can detect the illuminance of the outdoor environment 40 and theinterior of the showroom 20, respectively.

[0591] This fact is utilized in the following manner. Specifically,assume that the signals from the illuminance sensors 131, 132 areapplied to the radiation control unit 14 and that the illuminancedetected by the sensors is high. In this case, the light amount of theradiation beam emitted from the radiation unit 12 is increased toincrease the brightness of the image projected on the hologram screen.Thus, the noise light is rendered less conspicuous, and therecognizability of the image is improved.

[0592] In the case where the illuminance detected by the sensors is lowand the light amount of the radiation beam is large, in contrast, theimage is brightened often causing a halation. In such a case, the amountof the radiation beam 17 from the radiation unit 12 is reduced toimprove the visual recognizability of the image.

[0593] In the case where the illuminance sensors 131, 132 detect theilluminance of a value more than the value at which it is expected thatthe effect of the noise cannot be avoided even if the light amount ismaximized, the radiation unit 12 may be deactivated.

[0594] The controller is configured to activate or deactivate theradiation unit or adjust the sound volume of the speaker in accordancewith the sound volume within the viewing angle detected by the soundvolume sensor.

[0595] In the case where the sound of a certain decibel level isdetected in the viewing angle by the volume sensor, the viewer isassumed to have entered or reached the periphery of the viewing angle,and the controller activates the radiation unit and the speaker.

[0596] In the case where the volume sensor fails to detect a sound ofsome decibel level within the viewing angle, no viewer is assumed toexist within or around the viewing angle, so that the controllerdeactivates the radiation unit and the speaker.

[0597] Further, in the case where a noise higher than a predetermineddecibel level is detected by the volume sensor within the viewing angle,the controller adjusts the sound volume of the speaker upward so thatthe sound from the speaker may be clearly audible.

[0598] In the case where only a sound not more than a predeterminedsound level is detected by the volume sensor within the viewing angle,on the other hand, the interior of the viewing angle is regarded to bein quiet state, and the sound volume of the speaker is adjusted downwardby the controller not to give an uncomfortable feeling to the viewer.

[0599] The remaining component elements of the configuration are thesame as the corresponding component elements of the embodiment B1.

[0600] The image information displaying system according to thisembodiment can provide audio information as well as image informationand at the same time can adjust the sound volume of the audioinformation corresponding to the condition within the viewing angle.Thus, an even better eye-catching effect can be secured.

[0601] The use of a directional volume sensor having a reflector capableof collecting the sound in the viewing angle is more effective to detectthe sound volume within the viewing angle.

[0602] Embodiment B5

[0603] This embodiment will be explained with reference to the case inwhich, as shown in FIGS. 28 to 32, an image information displayingsystem is installed in an automotive vehicle constituting a mobile body.

[0604] As shown in FIGS. 28, 29, a display unit 100 including atransparent support 10 and a hologram screen 11 is suspended by use of asuspension 70 from the ceiling of a mobile body 7 between the driver'sseat 71 and the front passenger seat 72 at such a position that a viewer8 in the rear seat 73 can see the image information.

[0605] As shown in FIG. 28, the image information displaying system 1according to the present embodiment comprises a vibration sensor 133,and in response to the signal from the vibration sensor 133, the blur ofthe image signal due to the vibration of the mobile body is corrected bythe radiation control unit 14.

[0606] This configuration will be described in detail with reference toFIG. 31.

[0607] The signal from the vibration sensor 133 is applied to anelectrical correction circuit in the radiation control unit 14. Also,the image information is applied to the radiation unit 12 from a source120 such as a video deck. The electrical correction circuit of theradiation control unit 14 reversely corrects the vibration of the imageinformation inputted to the radiation unit 12, and the resulting imageinformation is radiated on the display unit 100 from the radiation unit12.

[0608] The other parts of the configuration are similar to thecorresponding parts of the embodiment B1.

[0609] The image information displaying system 1 is mounted on themobile body 7, and therefore the image information would fluctuate as itis presented to the viewer 8 unless some countermeasure is taken whilethe mobile body 7 is running. In this embodiment, however, the imageinformation is radiated from the radiation unit 12 after being correctedbased on the signal from the vibration sensor 133. Therefore, the effectof the vibration is offset and the image is free of blur.

[0610] The other functions and effects are the same as those of theembodiment B1.

[0611] The different points of the configuration of the informationdisplaying system 1 according to this embodiment will be explained.

[0612] As shown in FIG. 32, the radiation control unit 14 is adapted tosuppress, based on the signal from the vibration sensor 133, thevibrations of the radiation unit 12 due to the vibrations of the mobilebody 7.

[0613] The signal from the vibration sensor 133 is applied to avibration control mechanism 149 in the radiation unit 12 from theradiation control unit 14. Also, the image information, as in thepreceding case, is applied to the radiation unit 12 from a source 120such as a video deck. The radiation control unit 14 activates thevibration control mechanism 149 based on the signal of the vibrationsensor 133, so that the effect of the vibration of the mobile body 7 onthe radiation unit 12 is canceled.

[0614] In this configuration, the same effect is obtained as in theaforementioned configuration, and the viewer 8 can observe a correctimage free of blur.

[0615] Embodiment B6

[0616] This embodiment refers to the correction of the image informationby a central control unit.

[0617] The image information displaying system according to thisembodiment has a configuration similar to that of the first embodiment,and comprises a hologram screen and a radiation unit. The radiation unitis made up of a liquid crystal projector.

[0618] The image information distributed from the central control unitremains in normal state until it reaches the LCD of the liquid crystalprojector. The image 190 in normal state is shown in FIG. 33(c).

[0619] The radiation unit 12 is fixed at a position diagonally below thehologram screen 11. Therefore, the beam radiated from the radiation unit12 enters the hologram screen 11 from a diagonal direction. In manycases, therefore, as shown in FIG. 33(a), the image information isdeformed into a trapezoid with the result that a distorted image 191 isprojected on the screen. This is a trapezoidal distortion.

[0620] The amount of the trapezoidal distortion can be predetermined bycalculations on relative positions of the radiation unit 12 and thehologram screen 11. In this embodiment, the central control unit issupplied beforehand with the relative positions of the hologram screen11 and the radiation unit 12, and arithmetic operations are performedbased on the input relation. According to the result of the arithmeticoperations, the LCD signal of the liquid crystal projector constitutingthe radiation unit 12 is subjected to correction by uniform compressivecomplementation. As a result, a distorted image 192 as shown in FIG.33(b) is produced by the LCD signal.

[0621] The radiation beam containing this image 192 is radiated on thehologram screen 11, whereby the deformation due to the trapezoidaldistortion is offset by the distortion applied according to thearithmetic operations.

[0622] Thus, a normal image 190 as shown in FIG. 33(c) is displayed onthe hologram screen.

[0623] The other points are similar to those of the embodiment B1.

[0624] As described above, according to this embodiment, an imageinformation displaying system is obtained which can display a normalimage free of trapezoidal distortion. The image information displayingsystem proper is not required to correct the trapezoidal distortion, andtherefore requires no device for correcting the trapezoidal distortion.The image information displaying system can thus be reduced in cost. Theother functions and effects are similar to those of the embodiment B1.

[0625] Embodiment C1

[0626] A hologram displaying system according to this embodiment will beexplained with reference to FIGS. 34 to 40.

[0627] As shown in FIGS. 34 to 35, a hologram displaying system 1according to this embodiment comprises a hologram screen 11 and aprojector 12 for projecting an image beam 125 on the hologram screen 11.The distance A between the lower end 111 of the hologram screen 11 andthe floor surface 31 is 110 cm.

[0628] The center height C of the hologram screen is 140 cm above thefloor surface 31. The distance B from the upper end 112 to thehorizontal ceiling surface 32 is 100 cm. The distance E between the leftend 113 and the wall surface 33, and the distance between the right end114 and the wall surface 34 are both 35 cm.

[0629] The image beam 125 is projected on the hologram screen 11 at aprojection angle a of 35 degrees. The diagonal length of the hologramscreen 11 is 40 inches. The projection distance D of the image beam 125is 160 cm.

[0630] The projection distance D is the length between the center of thehologram screen 11 and a lens 120 of a projector constituting theprojector 12.

[0631] Now, the hologram displaying system as it is installed accordingto this embodiment will be explained with reference to FIG. 36.

[0632]FIG. 36 shows a showroom 20 in which the hologram displayingsystem 1 according to this embodiment is installed. The hologram screen11 is of transmission type, and is adhered to the window glass 20 in theshowroom by spraying water on the surface of the hologram screen 11. Theadhesive previously formed on the hologram screen 11 is an acrylic estercopolymer which forms a transparent film when dried.

[0633] A commodity 25 is exhibited behind the hologram screen 11.

[0634] As long as the image is not on display, the commodity 25 can beviewed through the hologram screen 11.

[0635] As shown in FIG. 34, the projector 12 is fixed by a fixing jig129 on the horizontal ceiling surface 32 of the showroom 20. The fixingjig 129 fixes the projector 12 at an inclination angle B of 35 degreesto the horizontal ceiling surface. The lens 120 for projecting the imagebeam of the projector 12 is movable.

[0636] The projector 12 is a commercially available liquid crystalprojector having a brightness of not less than 400 cd/m² (on conditionthat the image beam is normal white). Coefficients a and b of theprojector 12 are 4.6 and −23.7, respectively.

[0637] The projector, to hide it from the viewer 8, can be covered withsuch objects as a foliage plant to present a greater feeling of wonder,thus improving the eye-catching effect.

[0638] A trapezoidal distortion correction mechanism 14 is arranged onthe back of the horizontal ceiling surface 32 of the showroom 20. Thearrangement also includes an optical disk having an image recordedtherein and a reproduction unit 13 having the optical disk housedtherein. The reproduction unit 13, the trapezoidal distortion correctionmechanism 14 and the projector 12 are connected to each other by cable.

[0639] The image inputted from the reproduction unit 13 is reshaped bythe trapezoidal distortion correction mechanism 14 so that the image mayassume a correct shape when projected on the hologram screen 11. Afterthat, the trapezoidal distortion correction mechanism 14 sends out theimage to the projector 12.

[0640] The hologram screen 11 according to this embodiment has asandwiched structure in which at least one hologram element oftransmission type is attached to a PET film and another PET film isattached to a reflection surface thereof.

[0641] The viewing angle of the hologram screen according to thisembodiment is 35 degrees vertical and 60 degrees horizontal.

[0642] Now, the functions and effects of the embodiment will beexplained.

[0643] In the hologram displaying system 1 according to this embodiment,the hologram screen 11 is installed under the above-mentionedconditions, and therefore the viewing angle 89 is located just withinthe range of the line of sight of the viewer 8.

[0644] Consequently, the hologram displaying system 1 according to thisembodiment can display the image within the range of the line of sightof the viewer 8. Also, the transparency of the hologram screen 11 makesthe viewer 8 feel as if the image is projected in an empty space.

[0645] Thus, the hologram displaying system 1 according to thisembodiment has the effect of attracting the attention of the people,i.e., has an eye-catching effect.

[0646] As described above, according to this embodiment, a hologramdisplaying system is provided which can display a superior image and hasa good eye-catching effect.

[0647] With the hologram displaying system 1 according to thisembodiment, the hologram screen 11 is installed in such a manner thatthe lower end 111 thereof meets the above-mentioned conditions.

[0648] As a consequence, the hologram screen 11 is installed somedistance away from the floor surface 31 and thus a spatial margin iscreated around it. This prevents the heat from staying in thesurroundings of the hologram screen 11 and heating the hologram screen11.

[0649] As described above, in the hologram displaying system accordingto this embodiment, image distortion due to heat is prevented.

[0650] The hologram screen according to this embodiment, which is in theform of a flat plate, can assume other shapes such as tabular stripsforming a screen or a curtain suspended from the ceiling.

[0651] These shapes permit the hologram screen to be rolled up orotherwise retracted or housed when not used for effective utilization ofa limited space.

[0652] The hologram screen 11 according to this embodiment, which isattached on the window glass 20 in the showroom 2, can alternatively beinstalled by being fitted in an indoor partition or a commodity shelf.

[0653] The hologram screen 11 according to this embodiment can beinstalled by being attached on either the front or back of the windowglass 20.

[0654] In order to prevent the hologram screen 11 from coming off at thetime of cleaning or otherwise, as shown in FIGS. 37(c), 37(d), thehologram screen 11 can have a tapered section.

[0655] As an alternative, as shown in FIGS. 37(a), 37(b), the corners ofthe hologram screen 11 can be chamfered off. This chamfering can beeffected by cutting off the corners in straight fashion as shown in FIG.37(a), or by curving the corners as shown in FIG. 37(b).

[0656] With the hologram displaying system 1 according to thisembodiment, as shown in FIG. 38(a), the hologram screen 11 is installedas a single unit on which the image beam 125 is projected using a singleprojector 12.

[0657] Instead, as shown in FIG. 38(b), four hologram screens 11 can bearranged side by side to form a single large screen on which fourprojectors 12 can project the image beam 125.

[0658] Further, as shown in FIG. 38(c), the image beam 125 can beprojected on four hologram screens 11 from a single large projector 12.

[0659] Also, as shown in FIG. 39, nine hologram screens 11, arranged ina matrix of three by three to form a single large screen having adiagonal length of L, can be used with the hologram displaying system 1.

[0660] In the case where a plurality of hologram screens 11 are arrangedin the same plane to form a large single screen, the gap length dbetween adjacent hologram screens 11 is determined to some degree by thedistance between the viewer and the hologram screen 11. Specifically,the farther the viewer stands from the hologram screen 11, the less uglythe image appears even when the gap is so large as to fragment theimage.

[0661] In the case where the viewer stands several tens of meters awayfrom the screen, for example, even a gap as large as 10-odd cm may beallowable.

[0662] The images that can be displayed on this hologram displayingsystem include, in addition to commodity advertisements, information onsuch matters as outings, weather forecasting, traffic news, commoditycampaigns, new products, sales promotion means such as a quiz game, andalarm in case of an emergency. Also, the hologram displaying systemaccording to this embodiment can be used as a virtual exhibition shelffor introducing commodities that cannot be physically exhibited. Also,in combination with a touch screen, the hologram display screen can beused as a touch panel.

[0663] Further, with the hologram displaying system 1 according to thisembodiment, in order to display the full image with high quality on thehologram screen 11, the image is desirably finely adjusted using animage positioning mechanism or the like attached to the projector 12.

[0664] Since the hologram displaying system 1 according to thisembodiment is configured of the hologram screen 11 of transmission type,such an adjustment as described above is required to be conducted by theoperator observing the hologram screen 11 from the position of theviewer 8 shown in FIG. 1.

[0665] The hologram screen 11 of the hologram displaying system 1according to this embodiment can be installed on the ceiling, the wall,the floor, etc., as well as on the window glass 20.

[0666] Also, the hologram screen 11 can be attached to the window glass20 by use of adhesive tapes 191 or seals 192 as shown in FIG. 40. Inthis case, the whole edges of the hologram screen 11 may be fixed asshown in FIG. 40(a), or fixed only at the four corners as shown in FIG.40(b).

[0667] The interference fringes indispensable for the hologram screen 11to exhibit the functions thereof are very delicate and easily brokenunder a strong force. The use of the adhesive tapes 191 or the seals192, however, permits the hologram screen 11 to be detached with a smallforce. The hologram screen 11, after being fixed, can thus be reused inanother place.

[0668] The projector can be arranged outside the showroom and the imagebeam can be radiated from outside on the hologram screen attached on thewindow glass 20. In such a case, the image projected on the hologramscreen can be observed also from inside the showroom with equal effect.

[0669] Further, the hologram screen can be attached on either the frontor the back of the window glass 20 (i.e. either inside or outside theshowroom). The effect is the same for either case.

[0670] Embodiment C2

[0671] This embodiment refers to a hologram displaying system 1 with aprojector 12 installed on the floor surface as shown in FIGS. 41 to 43.

[0672] As shown in FIGS. 41 and 42, the hologram displaying system 1according to this embodiment is also installed in a showroom, andcomprises a hologram screen 11 attached on the window glass 20 and aprojector 12 fixed on a rest 16 and arranged on a floor surface 31.

[0673] With this hologram displaying system 1, the distance A is 130 cm,the center height C is 160 cm, the projection distance D is 160 cm, andthe distances E and E are both 35 cm. The projection angle α is 35degrees.

[0674] The hologram screen 11 of the hologram displaying system 1according to this embodiment has attached thereto a thermal stressalleviating film 119 composed of biaxial oriented PET.

[0675] The other points are the same as the corresponding points of theembodiment C1.

[0676] With the hologram displaying system 1 according to thisembodiment, the projector 12 is arranged under the hologram screen 11which in turn is located at the relative position described above.

[0677] As a result, the zero-order beam from the projector 12 can beprevented from intruding the line of sight of the viewer 8. Also, theviewing angle of the hologram screen 11 can be included in the range ofthe line of sight of the viewer 8. Thus a superior eye-catching effectcan be produced. Further, since the projector 12 is installed on thefloor surface, ceiling work is not required, thus facilitating theinstallation work. Also, the thermal stress alleviating film 119 has anadded effect of preventing the deformation of the interference fringesunder thermal stress.

[0678] The other functions and effects of this embodiment are similar tothose of the embodiment C1.

[0679] According to the embodiment C1 and this embodiment, the projector12 is installed above and under the hologram screen 11, respectively.This indicates that the projector 12 is located at points t1 and t2,respectively, in FIG. 43.

[0680] As shown in FIG. 43, the projection angle of α indicates that theprojector is installed on the circumference of the circle constitutingthe bottom surface of an assumed circular cone having an apex at thecenter 110 of the hologram screen 11.

[0681] Specifically, the projectors have the same projection angle awhen they are installed at position t1 above the hologram screen 11, atposition t2 under the hologram screen 11, at position t3 diagonallyabove the hologram screen 11 and at position t4 diagonally under thehologram screen 11.

[0682] Thus the installation of the projector on the circumference shownin FIG. 43 at the angle α of 20 to 50 degrees has the same effect as theembodiment C1.

[0683] Embodiment C3

[0684] This embodiment refers to the hologram displaying system 1further comprising two mirrors interposed between the hologram screen 11and the projector 12, as shown in FIG. 44.

[0685] As shown in FIG. 44, the hologram displaying system 1 accordingto this embodiment comprises a hologram screen 11 supported on a supportmember 40 on a base 401, a first mirror 41 supported on a support member404, a projector 12 arranged on a rest 402, and a rest 403 and a secondmirror 41 arranged above the projector 12.

[0686] The other points are similar to those of the embodiment C1.

[0687] In the hologram displaying system 4 according to this embodiment,the image beam emitted from the projector 12 is reflected on the firstmirror 41 and proceeds to the second mirror 42. The image beam, afterbeing reflected on the second mirror 42, reaches the hologram screen 11on which the image is projected.

[0688] With the hologram displaying system 4 according to thisembodiment, the distance is short between the projector 12 and thehologram screen 11. The fact that the image beam is reflected on thefirst mirror 41 and the second mirror 42, however, makes it possible toproject an image not less than 40 inches in size while at the same timeforming a long beam path as required to secure the incident angle of 35degrees.

[0689] Consequently, the hologram displaying system 4 that can beinstalled in a limited space is realized.

[0690] The beam path length can be adjusted by employing either aconcave or a convex mirror. Also, the difference of the beam path lengthbetween the upper and lower ends of the hologram screen and the verticalout-of-focus condition can be adjusted by coloring the mirrors and thehologram screen.

[0691] Especially, the use of an aspheric mirror will have the effect ofcorrecting the trapezoidal distortion.

[0692] Embodiment C4

[0693] This embodiment refers to a hologram displaying system 1comprising a projector 12 and a hologram screen 11 suspended from thehorizontal ceiling surface 32 by means of arms 117, 127 as shown in FIG.45.

[0694] With the hologram displaying system 1, the hologram screen 11 isinstalled diagonally to secure some distance between the hologramdisplaying system 1 and the hologram screen 11 and thus to secure theprojection distance D of the image beam.

[0695] The other parts of the configuration, the functions and effectsof this embodiment are similar to those of the embodiment C1.

[0696] Embodiment C5

[0697] In the hologram displaying system according to this embodiment,the image beam issued from the projector is reflected on a mirror drivenby a drive unit to change the angle thereof. In this way, an image isformed on a plurality of hologram screens.

[0698] Further, a rail is laid on the ceiling surface and the floorsurface to move the projector alone or with the mirror to produce afresh dramatic presentation effect.

[0699] Embodiment C6

[0700] This embodiment refers to a hologram displaying system using ahologram screen configured of a mirror and a hologram element attachedto each other, as shown in FIGS. 46 and 47.

[0701] The hologram screen 61 according to this embodiment includes ahologram element 62 and a mirror 63 attached to each other as shown inFIG. 47.

[0702] The image beam 125 is projected on the hologram screen 61 by useof the projector 12 from the side nearer to the hologram element 62.

[0703] The other points are similar to the corresponding points of theembodiment C1.

[0704] The image is projected on the hologram screen 61 according tothis embodiment in the following-described manner.

[0705] As shown in FIG. 47, the image beam 125 is projected from theprojector 12. The image beam 125 is transmitted through the hologramelement 62 of transmission type and reaches the mirror 63. The imagebeam 125 is reflected on the surface of the mirror 63 and enters thehologram element 62 again.

[0706] The hologram element 62 is of transmission type, and theinterference fringes in the hologram element 62 diffracts only the imagebeam 125 reflected from the mirror 63, in the direction of arrow 650. Asa result, the projector 125 arranged nearer to the hologram element 62appears as if located at the position designated by numeral 65 nearer tothe mirror 63 and it appears as if the image beam 655 is projected fromthe particular position.

[0707] As shown in FIG. 46, assume that the hologram 61 is installed ata sufficiently bright place. The surrounding scenes 85 are imaged on themirror 63 (the arrow 66 in FIG. 47 represents the trace of the beamprojected from the scenes 85). The person 8 standing in front of thehologram screen 61 is also reflected on the mirror 63. In this way, theimage 850 of the scenes 85 and the image 80 of the person 8 aredisplayed on the hologram screen 61.

[0708] As described above, the surrounding scenes 85, the person 8standing in front of the hologram screen 61 and the image reproduced bythe image beam 125 projected from the projector 12 are all displayed onthe hologram screen 61.

[0709] Consequently, the person 8 can feel as if any of the scenes 85 onhis/her background is displayed on the hologram 61 and the image isdisplayed thereon.

[0710] The viewer himself/herself thus appears in the projected image.In this way, a dramatic presentation improving the eye-catching effectcan be realized and a synthetic picture can be made.

[0711] Embodiment C7

[0712] This embodiment refers to a hologram displaying system configuredof an antireflection film or a polarizing film attached to a hologramscreen as shown in FIG. 50.

[0713] As shown in FIG. 50, the hologram displaying system 1 accordingto this embodiment, like the first embodiment, comprises a hologramscreen 11 attached to the inner surface 201 of the window glass 20 and aprojector 12 fixed on the horizontal ceiling surface 32.

[0714] A polarizing film 791 is attached to the indoor side of thehologram screen 11, and an antireflection film 792 is arranged on theoutdoor side through the window glass 20. In FIG. 50, reference numeral78 designates an indoor background, numeral 7 an outdoor environment,and numeral 79 an outdoor background. The other points are similar tothe first embodiment.

[0715] In the hologram displaying system 1 according to this embodiment,the following phenomenon occurs when the viewer observes the hologramscreen.

[0716] An illumination unit 75 is arranged on the horizontal ceilingsurface 32 of the showroom 2. The illumination beam emitted from theillumination unit 75 is reflected on the indoor background 78 or thelike and the beam 751 reflected from it reaches the viewer 8 through thehologram screen 11.

[0717] In the outdoor environment 7, on the other hand, the directsunlight 701 from the sun 70 is reflected on the outdoor background 79or the like. The beam 702 thus reflected is reflected on the windowglass 20 and reaches the viewer 8.

[0718] Suppose that the polarizing film 791 according to the embodimentis lacking. The reflected beam 751 would be superposed on the imageprojected on the hologram screen, so that the background brightnessincreases for a reduced image contrast.

[0719] Assume, again, that the antireflection film 792 according to thisembodiment is lacking. The direct sunlight 701 and the reflected beam702 would be reflected on the window glass 20. Therefore, the outdoorbeam brightness would increase and the image contrast would be reduced.

[0720] The image contrast, as described above, is determined as (imagewhite screen brightness+background brightness+external lightbrightness)/(image black screen brightness+backgroundbrightness+external light brightness).

[0721] As described above, the background brightness and the externallight brightness can be reduced and the image contrast can be improvedfurther by providing the polarizing film 791 and the antireflection film792 on the hologram screen 1.

[0722] Thus, the image appearance can be produced which secures asufficient eye-catching effect.

[0723] Embodiment C8

[0724] This embodiment refers to a hologram screen used with a hologramdisplaying system.

[0725] As shown in FIGS. 51(a) to 51(f), 52(a) to 52(f) and 53(a) to53(f), the hologram screen 11 is not limited to a specific shape, but ahologram screen 11 of the desired shape including those described or notdescribed in the accompanying drawings can be used with the hologramdisplaying system.

[0726] In each of the hologram screens 11 shown in FIGS. 51(a) to 51(f),52(a) to 52(f) and 53(a) to 53(f), the lower end 111 is represented by astraight side (FIGS. 51(a), 52(a), 53(b)), or in the case of an apex oran arc, by a straight line passing the lowest point thereof (FIGS.51(d), 52(b), 53(a)). In the case where the lowest portion substantiallyfails to contribute to the image, another portion contributing to theimage constitutes the lowest end (FIGS. 53(e), 53(f)).

[0727] The center of each hologram screen 11 of FIGS. 51(a) to 51(f),52(a) to 52(f) and 53(a) to 53(f) coincides with the gravitationalcenter thereof. The center of the hologram screen shown in FIGS. 53e, 53f, however, is the gravitational center of the portion contributing tothe image.

[0728] When the image beam is projected on the hologram screen 11, theimage is not necessarily formed over the entire surface of the hologramscreen 11 but, as shown in FIG. 54, the image 100 can be projectedpartially using the zoom function of the projector.

[0729] The other points are similar to those of the embodiment C1.

[0730] Also, even when using the hologram screen 11 described above, thesame functions and effects as those of the first embodiment can beobtained.

[0731] Embodiment C9

[0732] This embodiment refers to the place of installation of thehologram displaying system as shown in FIGS. 55 and 56.

[0733] As shown in FIG. 55, the hologram displaying system according tothis embodiment has a configuration similar to that of the firstembodiment. The floor surface 311 on which the viewer 8 stands has aheight different from the floor surface 312 in the showroom 2 in whichthe hologram displaying system 1 is installed.

[0734] In this case, the lower end 111 of the hologram screen 11 is 80to 180 cm above the floor surface 311 (designated A in FIG. 55), or thecenter of the hologram screen 11 is located 110 to 210 cm above thefloor surface 311 (designated by C in FIG. 55).

[0735] Also, as shown in FIG. 56, the hologram displaying system 1according to this embodiment has a configuration similar to that of thefirst embodiment, and is installed in the showroom 2 having an inclinedceiling.

[0736] In this showroom 2, the straight line perpendicular to thesurface 118 on which the hologram screen 11 is installed is not parallelto the ceiling surface. The plane containing the straight lineperpendicular to the installation surface 118 is considered as ahorizontal ceiling surface 32. The angle B formed by the horizontalceiling surface 32 and the projector 12 is an inclination angle which is20 to 50 degrees.

What is claimed is:
 1. An image information displaying systemcomprising: a transparent support; a hologram screen attached to thetransparent support; a projector for projecting image information ontothe hologram screen; a sensor for sensing ambient conditions in aviewing angle of the hologram screen; and a controller for controllingthe projector according to signals from the sensor.
 2. The system ofclaim 1, wherein the viewing angle corresponds to an area whosebrightness is K0/2 or over, where K0 is a brightness value at a frontcenter point of the hologram screen).
 3. The system of any one of claims1 and 2, wherein the sensor is an illuminance sensor.
 4. The system ofclaim 1, further comprising: a speaker for providing audio information,wherein the sensor is a volume sensor.
 5. The system of claim 1, whereinthe sensor is designed to sense people who enter the viewing angle. 6.The system of claim 1, wherein the system is installed in a mobile body.7. The system of claim 6, wherein the system is installed between twoseats arranged in the mobile body.
 8. The system of any one of claims 6and 7, wherein the hologram screen is retractable when not used.
 9. Thesystem of any one of claims 6 and 7, wherein the sensor is a vibrationsensor, and the controller corrects, according to signals from thevibration sensor, a blur of image information due to the vibration ofthe mobile body.
 10. The system of any one of claims 6 and 7, whereinthe sensor is a vibration sensor, and the controller suppresses,according to signals from the vibration sensor, the vibration of theprojector due to the vibration of the mobile body.
 11. The system ofclaim 1, wherein the system is controlled by a central control unit thatis connected to the system through a communication circuit.
 12. Thesystem of claim 11, wherein the central control unit receives signalsfrom the sensor through the communication circuit, and according to thesignals, controls the projector.
 13. The system of claim 1, wherein thehologram screen has a diffuser recorded thereon.
 14. An imageinformation displaying system comprising a transparent support, ahologram screen attached to said transparent support and a radiationunit for radiating image information on said hologram screen; said imageinformation displaying system being so configured as to be controlled bya central control unit connected through a communication line.
 15. Animage information displaying system according to claim 14, comprisingselected one of first and second configurations; said firstconfiguration being that said central control unit performs the processof correcting said image information; said second configuration beingthat a relay is interposed between said central control unit and saidimage information displaying system, and a selected one of said centralcontrol unit and said relay performs the process of correcting saidimage information.
 16. An image information displaying system accordingto claim 15, wherein said process of correcting said image informationis correcting a trapezoidal distortion.
 17. An image informationdisplaying system according to claim 15, wherein said process ofcorrecting said image information is at least a selected one of coloradjustment, color correction, image position adjustment, imagebrightness adjustment and image contrast adjustment.
 18. An imageinformation displaying system according to claim 14, further comprisingmeans for supplying audio information, wherein a selected one of saidcentral control unit and said relay is capable of correcting said audioinformation.
 19. An image information displaying system according toclaim 14, further comprising a sensor for detecting the ambientcondition in the viewing angle of said hologram screen and a radiationcontrol unit for controlling said radiation unit based on the signalfrom said sensor.
 20. An image information displaying system accordingto claim 19, wherein said viewing angle is in a range not less thanK0/4, where K0 is the brightness value at the center front of thehologram screen.
 21. An image information displaying system according toclaim 19, wherein said sensor is an illuminance sensor.
 22. An imageinformation displaying system according to claim 19, wherein said sensoris a sound volume sensor.
 23. An image information displaying systemaccording to claim 19, wherein said sensor detects the entry of a viewerinto said viewing angle.
 24. An image information displaying systemaccording to claim 19, installed on a mobile body.
 25. An imageinformation displaying system according to claim 24, installed betweenat least two seats in a mobile body.
 26. An image information displayingsystem according to claim 24, wherein said hologram screen isretractable when not in use.
 27. An image information displaying systemaccording to claim 24, wherein said sensor is a vibration sensor, andsaid radiation control unit corrects the blur of said image informationcaused by the vibration of said mobile body, based on the signal fromsaid vibration sensor.
 28. An image information displaying systemaccording to claim 24, wherein said sensor is a vibration sensor, andsaid radiation control unit suppresses the blur of said radiation unitcaused by the vibration of said mobile body, based on the signal fromsaid vibration sensor.
 29. An image information displaying systemaccording to claim 19, wherein selected one of said central control unitand said relay receives a signal from said sensor, through saidcommunication line, and controls said radiation control unit based onsaid signal.
 30. An image information displaying system according toclaim 14, wherein a diffuser is recorded in said hologram screen.
 31. Ahologram displaying system comprising a hologram screen and a projectorfor projecting an image beam on said hologram screen, wherein the lowerend of said hologram screen is at the distance of 80 to 180 cm from thefloor surface.
 32. A hologram displaying system according to claim 31,further comprising a mechanism for correcting a trapezoidal distortion.33. A hologram displaying system according to claim 31, wherein thediagonal length of said hologram screen is not less than 30 inches andthe projection distance of the image beam is not less than 90 cm.
 34. Ahologram displaying system according to claim 31, wherein the diagonallength of said hologram screen and said projection distance have arelation defined as y=ax+b, where x is the diagonal length in inches, yis the projection distance in cm and a and b are coefficients determinedby the projector.
 35. A hologram displaying system according to claim31, wherein said hologram screen is installed in an environment wherethe contrast is not less than 1.5, said contrast being defined as (imagewhite screen brightness+background brightness+external lightbrightness)/(image black screen brightness+backgroundbrightness+external light brightness).
 36. A hologram displaying systemaccording to claim 31, wherein said hologram screen has a selected oneof first and second configurations; said first configuration being thatat least a corner of said hologram screen is chamfered; said secondconfiguration being that said hologram screen has a tapered section. 37.A hologram displaying system according to claim 31, wherein adhesive ispreviously formed on the surface of said hologram screen, said hologramscreen being adhered to glass by spraying water on the surface of thehologram screen before it is applied to the glass.
 38. A hologramdisplaying system according to claim 31, wherein said projector is isfixed at an inclination angle of 20 to 50 degrees to the horizontalceiling surface by a fixing jig.
 39. A hologram displaying systemcomprising a hologram screen and a projector for projecting an imagebeam on said hologram screen, wherein the center height of said hologramscreen is 110 to 210 cm from the floor surface.
 40. A hologramdisplaying system according to claim 39, further comprising a mechanismfor correcting a trapezoidal distortion.
 41. A hologram displayingsystem according to claim 39, wherein the diagonal length of saidhologram screen is not less than 30 inches and the projection distanceof the image beam is not less than 90 cm.
 42. A hologram displayingsystem according to claim 39, wherein the diagonal length of saidhologram screen and said projection distance have a relation defined asy=ax+b, where x is the diagonal length in inches, y is the projectiondistance in cm and a and b are coefficients determined by the projector.43. A hologram displaying system according to claim 39, wherein saidhologram screen is installed in an environment where the contrast is notless than 1.5, said contrast being defined as (image white screenbrightness+background brightness+external light brightness)/(image blackscreen brightness+background brightness+external light brightness). 44.A hologram displaying system according to claim 39, wherein saidhologram screen has selected one of first and second configurations;said first configuration being that at least a corner of said hologramscreen is chamfered; said second configuration being that said hologramscreen has a tapered section.
 45. A hologram displaying system accordingto claim 39, wherein adhesive is previously formed on the surface ofsaid hologram screen, said hologram screen being adhered to glass byspraying water on the surface of the hologram screen before it isapplied to the glass.
 46. A hologram displaying system according toclaim 39, wherein said projector is fixed at an inclination angle of 20to 50 degrees to the horizontal ceiling surface by a fixing jig.
 47. Ahologram displaying system comprising a hologram screen and a projectorfor projecting an image beam on said hologram screen, wherein theprojection angle of said projector to said hologram screen is 20 to 50degrees.
 48. A hologram displaying system according to claim 47, furthercomprising a mechanism for correcting a trapezoidal distortion.
 49. Ahologram displaying system according to claim 47, wherein the diagonallength of said hologram screen is not less than 30 inches and theprojection distance of the image beam is not less than 90 cm.
 50. Ahologram displaying system according to claim 47, wherein the diagonallength of said hologram screen and said projection distance have arelation defined as y=ax+b, where x is the diagonal length in inches, yis the projection distance in cm and a and b are coefficients determinedby the projector.
 51. A hologram displaying system according to claim47, wherein said hologram screen is installed in an environment wherethe contrast is not less than 1.5, said contrast being defined as (imagewhite screen brightness+background brightness+external lightbrightness)/(image black screen brightness+backgroundbrightness+external light brightness).
 52. A hologram displaying systemaccording to claim 47, wherein said hologram screen has a selected oneof first and second configurations; said first configuration being thatat least a corner of said hologram screen is chamfered; said secondconfiguration being that said hologram screen has a tapered section. 53.A hologram displaying system according to claim 47, wherein adhesive ispreviously formed on the surface of said hologram screen, said hologramscreen being adhered to glass by spraying water on the surface of thehologram screen before it is applied to the glass.
 54. A hologramdisplaying system according to claim 47, wherein said projector is fixedat an inclination angle of 20 to 50 degrees to the horizontal ceilingsurface by a fixing jig.